software

• SooperLooper - A live looping sampler; an extremely valuable tool for the live, solo performances I like to do.
• Ardour - a great DAW. I only wish it had MIDI sequencing. I use it to record my performances and then chop out the boring parts.
• Rosegarden - Like Ardour in many respects, but less featured as a DAW, but has MIDI sequencing and music typesetting.
• Fluidsynth - A sample based softsynth. Can make many sounds with minimal effort, but I find its sample-based nature restrictive to my style.
• Jack - The server and library that synchronizes all audio data. Necessary for nearly any Linux audio work.

hardware

• M-audio MK-461C keyboard - happy with it as my first keyboard, but I'll want something better if I ever get good with keys.
• Roland TD-3 drum module; PD-8, CY-8, etc-8 drum pads - loads of fun. I wish I could have afforded better pads, and more of them.
• Behringer BCF2000 MIDI controller - 8 motorized faders and some knobs. Works awesomely and was very affordable. Through USB, also provides a traditional MIDI input and 2 outputs, for USB-less MIDI hardware.
• Behringer FCB1010 MIDI foot controller - I use this to control SooperLooper. Very well made. Very programmable, but doing so can be time-consuming.
• Sharp MM-20 laptop - gets the job done but is a bit slow.
• Echo indigo io PCMCIA audio interface - a billion times better than my laptop's built-in audio, and works with Linux after building a custom ALSA.
• Non-spectacular home-built PC - faster than my laptop.
• M-audio Delta 1010 - Had to get an M-audio card since they are nearly the only professional interfaces that work in linux, excepting RME which is too expensive for me. Luckly, it has not yet broken like everything else I've had from M-audio.

failures

Just as important are the things I don't own.

• M-audio Audiophile USB (audio interface) - I initially got this for my laptop, but it broke after a couple weeks of moderate use. Latency was unacceptably high too, which is partially due to poor drivers in Linux.
• Freewheeling 0.5pre4 - A live looping tool similar in scope to SooperLooper. It got canned because it consumed 85% of my CPU in idle state and liked to crash. Future versions could be better.
• M-audio "trigger finger" MIDI pad thinger - better than nothing; could have better feel. This used to be in the non-failures, but after a few months of light use, two of the knobs on this thing broke such that they send random data whenever I touch any part of the case. I'd return it if I could. Being the second thing from M-audio that has broken shortly after purchase under normal use, I don't think I'll be buying any more from them.