Things that are not plugins!

• ''Note: For more information on digital audio workstations see the Wikipedia article.

• Cakewalk SONAR: A professional's tool that does everything you need it to do. Better than Cubase, and not a memory hog. Comes with a bunch of nice plugins depending on which version you get. If you're a rich bastard like Reisen-Udongein-Inaba, try getting this. The entry level edition contains the core program with a few plugins, but is good if you need only that functionality.
• Fruity Loops / FL Studio: Very easy interface, used to make loops (duh.) Usually a no-brainer for beginners and wannabe rappers. Good for MIDI, bad for recorded audio.
• LMMS - Linux MultiMedia Studio: A free alternative to FL, virtually equal in functionality in its Windows incarnation (while pretty much no VST you'd care to use works for Linux.)
• MAGIX Music Maker: Still a good choice, it's better than 10 years ago when it was the poor man's Cubase meets the poor man's Fruity Loops.
• Steinberg CUBASE: The professional software. Used in most recording environments and full of effects. On the other hand, a memory hog extravaganza.
• REAPER: A newcomer DAW, cheap, constantly updated, and works well.
• Record: By the same company that developed Reason and done with a similarly unconventional approach. If you only want to record stuff and don't care about synths, or if you love Reason, you might like it. Reportedly uses some sort of nazi USB antipiracy thingy that prevents you from saving if you ever forget to plug it in. Like Reason it (at the time of writing) has no support for VST/AU/DX plugins and has no MIDI out, making it pig disgusting. If you want to use Reason and recorded audio you're better off ReWiring Reason to a better DAW.
• Logic Pro: Mac only. The learning curve is as follows: http://img69.imageshack.us/img69/7130/lolxe.jpg. It's actually pretty powerful and customizable! No VSTs however because Apple enjoys the incompatible AU format and fascism.
• GarageBand: Mac only. Don't want to deal with the complexity of Logic? Don't worry! Just buy a microphone from the Apple Store, launch Garage Band; depending on your age, select the Alternative, Songwriter, or Blues preset; press record, and then you too can sing about global warming and the plight of Palestinian people!
• Ableton Live: Windows and Mac. What all the cool kids use nowadays. Famous for it's 'session' view which basically splits up your instruments/loops into multiple launchable, loopable clips on a big grid - excellent for electronic music.

• ''Note: See the Wikipedia article for trackers and more in general check out the wiki pages for audio software.

• Psycle: A more 'graphical' tracker with support for VST instruments and effects.
• Renoise: We conjure the spirits of the music with our spreadsheets.
• Modplug: Renoise for poor people, and those that love the serenade of an 8-bit square wave. If you're modest like Reisen-Udongein-Inaba you can even make decent music with it. Be sure to register at the forum and check the Development Corner if you want the latest betas.
• NitroTracker: Fasttracker 2 styled tracker for the Nintendo DS with a promising future. Recently became open-source.
• GoatTracker: A crossplatform music editor for creating Commodore 64 music.
• Raster Music Tracker: Deliciously detuned Atari XE/XL music.

These are trackers that rely on certain soundchips for synthesis.

• AdlibTracker-II: Subz3ro's FM tracker, no sampling (requires OPL3-FM compatible soundchip or emulation, such as the one in DOSBox). Now open-source!
• edlib 1.05a The FM tracker that pushed OPL2-FM to it's limits. Harder to learn than most trackers. Comes with awesome tunes (be sure to check these too).
• maxYMiser: Tracker for the Atari ST.

• Reason: Extremely fun to play with once you've been through the very intimidating first few hours. But to use it in songs with vocals or real instruments, it is necessary to use it ReWired (virtually every DAW supports this but it's a pain, even when you're experienced, because the lack of total recall can fuck up your project if you don't save compulsively multiple versions). You can use it with Record, another software by Propellerheads. No VST/Au plug-in support (but you can think of it as a huge VST itself). You can finally record sound (as in, press REC and save the input of a microphone! WOW!) in a somewhat sane fashion in version 5! Great job on delivering this feature less than a decade after everyone requested it, guys!
• KORG DS-10 & DS-10+: Making it sound good and unlike the very few presets it comes with requires familiarity with programming synths, using clever cabling hacks, and tracking down mistranslations of the huge Japanese strategy guide sold separately. That makes it pretty braggable to fellow nerds.
• ReBirth: Win/Mac OS 9. Two 303s, a 808, a 909 - back when you were only this tall, that's all we needed to have acid techno, and we liked it that way. Free (will ask to register and further bullshit), old (1997!), very unsupported. Can be used in Reason - but I'd be suprised if it still works in 64-bits land. Recently ported to iPhone and its retarded cousins, $7.
• Hobnox Audiotool: Pretty much a Flash-based ReBirth. Synths and effects. Seems you must register and make your files public on their site to save your stuff, and I bet you can't export to a lossless format, but google "Stereo mix recording" (windows) or "audio hijack" (mac) to learn how to record your browser's output.

• Audacity: A very limited free recording software. Useless for tracking and MIDI editing.
• Goldwave: Pretty capable and straightforward commercial wave editor. Has a mathematical expression evaluator amongst others.
• Sound Forge: A reputable audio editor. Costs money.

• Vocaloid: Hatsune Miku - and a voice emulation software. As for all good things, it's NOT FREE.
• UTAU: Reputedly the poor man's Vocaloid.

• AT&T Natural Voices Demo: The "uncensored" version.

• GASHISOFT GXSCC: Enjoy converting your MIDI into NES-like sounds! (Engrish OK!)

• MidEdit: Open-source midi editor for J2ME phones, piano-roll interface. COOL FREE RINGTONES on the go!
• Vibe: Modded midi sequencer for J2ME. Much easier to use than MidEdit but not quite as many features.
• Mario Paint: Provides 15 different instruments you can use over the WHOLE C Major scale! Fourth notes, chords, tempo and time signature support! Can do animated color artwork!
  • "Advanced Mario Sequencer" The above, on YOUR COMPUTER. The download contains a .sf2 soundfont that you can use separately in almost any sampling software (the soundfont format is one of the most widely supported).
• Microsoft Songsmith: It has a "HAPPY" and a "JAZZY" slider! I recommend having the "HAPPY" and "JAZZY" sliders all the way to the right!

Things that are plugins!

• Synth1: This Windows-only VST synth is pretty nice if you wanna learn how to program synths, because it is free, sounds more than decent, has conventional and simple controls, has a good "turn the buttons and hear what happens" factor, has many free preset packs available (default ones aren't great), has a lot of tutorials written especially for it, and can be used to follow generic tutorials.
• SuperWave P8: COOL FREE SUPERSAWS.
• TruePianos: A hybrid physical modeling synthesis/sample based piano VST (also available standalone.) Not much to say about it other than it sounds great and offers a good variety to its sound. Costs money.
• 4Front Piano Module: Similar to above, only lower quality and free.
• Magical 8bit Plug: Beep boop bop bip.
• Alchemy: High quality additive synthesis, amongst other things. Disclaimer: Does not turn lead to gold.
• z3ta+: Older, but respectable virtual analog. Retails at $19.99 USVC.

• Crazy Ivan: Feed it anything, turn knobs, ear-rape ensues. (His other filters are worth a try too).
• CamelPhat: Makes things phatter. Offers very nice distortion and filters (amongst other things), great for bringing out those kicks and bass. Costs money.
• CamelCrusher: Free (lite) version of the above. Two distortion types, one resonant LP filter, and compressor.
• dblue Glitch: Provides a number of ways to fuck up audio, also free.
• Nasty Shaper: Interesting waveshaping distortion.
• Ohmicide:Melohman: Lovely multiband distortion ♥. Costs money.
• Bass Chorus: A chorus effect that promises to leave base frequencies intact. VST/DX
• Clone Ensemble: Creates an entire ensemble out of a single voice. Demo version is free but limited. VST/DX

• sfz: SoundFont player. Useful and free!
• Grizzly: A simple and free 8 pad drum sampler VST. Does its job well.
• Battery: Drum sampler VST by Native Instruments. Fully featured, easy to work with, and comes with a large library of drum samples. Costs money.

• jBridge: For running 32bit plugins in 64bit hosts and visa versa. Doesn't work with every plugin, but it's worth investigating if you're running a x64 system. Costs money.

• VOPM official page | VOPM unofficial manual and OS X version: This VST emulates a YM2151 chip, which sounds very close to the Mega Drive's YM2612 and supports the same patches. However, importing OPM files didn't work at all on my Mac, so I tried it in Windows with the demo of Renoise, but the plug-in crashed all the time.
• OPM patches: Patches from almost every song of every Genesis game ever.
• TFM Music Maker & VOPMxTFI: Tracker emulating a YM2203, also a similar-sounding chip supporting the same patches. Works well in Wine. Default buffer settings very low, raise if it skips. You will need to use the command-line only VOPMxTFI to convert the patches.
• If the SEGA-CD coder who wandered into SAoVQ is still around, I have read in the documentation that it is possible to export music made in TFM in a format that can be used in basiegaxorz, which means that it should be possible to play it back on real hardware (then record it in glorious analog on cassette tape), or at least play it with Kega, which has the most accurate YM2612 emulation AFAIK.
• Example track made with this process (bitcrushed voice added separately)
• I don't know much about FM synthesis or Yamaha soundchips so maybe I'm doing it wrong or got some details wrong in this section. Anyway, I found this process accurate enough to get the characteristic FM metallic edge I wanted.

• VFX for OS X is the driver for a hardware unit that can run VST, but it has the nice side-effect of letting you running Windows VST through wine. However, routing the audio and midi is a pain. You'll need soundflower, and to make an aggregate device and to enable the IAC driver in Audio MIDI Setup. I only managed to send MIDI from a native app to a windows VST and receive the sound in my app. Only one stereo audio channel available - and it has to be the system's default I/O. In theory it should be possible to run filters but I did not manage to send it audio at all. (Similar solutions exist for Linux, I hear they work better.)

• <html><s></html>BPM Analyzer: Accurately determine the BPM of a song. It's free but requires signing up.<html></s></html> Original source gone, go here instead.
• BPM/FPS calculator: Online tool for synchronizing framerate and musical tempo. Useful for animators.

• WolframTones: Oh man this is awesome. Please don't use it.

• KVR: For all your plugin needs.
• The Freesound Project: Large library of sounds licensed under Creative Commons.

• Sound On Sound Articles: Technique: Articles published in Sound On Sound focusing on digital audio production. Very useful information. People interested in sound synthesis in particular should make sure to check out Synth Secrets.
• How to program analog synthesizers: 20 min. video by a guy who knows his stuff. A good primer if you wanna man up and pretend the thousands of perfectly good presets available for your VSTs don't exist.
• PXtone manual by Gryzor87 (Hydorah). Pxtone itself was created to make the music of Cave Story, sort of a lo-fi tracker/sequencer. Even if you don't care about using this program, the PDF is worth a read for all its interesting asides about old-school VGM composition technique, with all the files needed to listen to examples in the archive. (Win required)