I use it for both recording our live rehearsals/jams (which is why I like things like being able to arm/unarm tracks/change their inputs while recording), as well as composing and recording songs (using both real instruments and softsynths). I'm not a great musician, though...
I use a SADiE system at work to record/edit dialogue for a cartoon series. I will be mixing it down too, but we haven't hit that production stage!
Oh, this is about REAPER. SOrry
Outside of work, I'm a musician, with a number of recording project on the go at any given time. I've been trialing a few different DAW programs for home use lately - I actually picked up an Mbox a while back, but I'm finding Pro Tools far too restrictive in terms of expandability. Having to pay extra for the ability to use VST plugins, or export an MP3, that sort of thing. After trying REAPER, and realising how much more performance it can eke out of my hardware, I've found myself going to it more and more for demo work etc. Recently I did a clean re-install of my system and didn't even bother to load Pro Tools back on.
Hmm, must be about time to register!
I'm pretty much using REAPER as a virtual tape machine/mixer... I don't do any loop based stuff, and my MIDI work has been limited to recording performances & minor fine tuning. I like to render my MIDI tracks to audio once the performance is done, and I really like that REAPER can have MIDI & wave data co-existing on a track. You can Apply the FX as a new take & mute the VSTi, but still have the MIDI data there if you need to tweak later.
I don't have anything online that was done with REAPER, as I'm still very much transitioning into the program... However my band's CD was produced in Cubase SX using much the same workflow. Audio (and video) clips can be found at http://www.thethirdending.com/media.shtml
I'm trying to convince the rest of the guys to go with REAPER this time around
At work I use Protools to edit/design/mix a 40 minute show. To tell you the truth, our old G4/400MHz PT 5.1.3 MacOS9 rig with 640MB RAM and 3 DSP farms worked better than the 1GB, 1.8GHz G4 PT6.4.1 otherwise-same-rig. And PT7.3LE doesn't work really well on my trusty little Athlon2500XP 1GB home rig.
But Reaper does. I'm mixing 30+ tracks with EQs and FX of old tracker songs and old material without trouble. It works nicely with my MCU. I'm not using it for sound design yet. Vegas and PTle work too well for that for small projects like that, but I may get there once I rename all my fx files with Soundminer.
So I use it for fun mixing at home. Love it. Payed for it.