Lets see....
Mac Pro 5,1 (50%+ - Main Number cruncher and video editor), MacBook Air 11" (25% - Research and portable), MacBook White (5% - Optical drive and presentations), PowerBook G4 (5% - Photography), iMac White Intel (5%), PowerMac G4 MDD (iTunes Jukebox and Server so is always "on and in use" despite me never using its mouse and keyboard really), PowerBook 1400c/166 (5% - Lovely for typing and editing text), PowerMac 8100, 8200, G4 AGP, 7500, various Consumer G3s and some older PPC and 68K Macs - the rest of the time.
- I use pretty much every machine I own at some point, but breaking it into percent would get very fiddly very fast (Since I Own and use >10 Macs), I also use a iPad 3G, Sony XPeria X8 and various iPods with this stuff.