I had been using a Mac (G4) exclusively for computer music production (Logic Audio) up thru the end of 2001. I switched to PC (Cakewalk Sonar) for three reasons: for compatibility (the majority of people here are PC users), the majority of arranger keyboard supported music programs & arranger KB software utilities are ONLY available on the PC-Windows, and PC music programs have significantly improved recently to make them a viable alternative for even the most critical software demands of computer music production. Previously only Mac programs were this good. You also get MORE for your money on both the hardware & software side with a PC. I admit that I still love the Mac platform though. Afterall, I've been a die hard Mac fan for over 12 years. Jedi, your iMac will provide everthing you need to make GREAT music so don't worry if the majority of people here are PC users. My all time FAV music digital audio/midi sequencer (only available on the Mac platform ) is Digital Performer, by Mark of the Unicorn. Jedi, if you don't already have it, you definitely owe yourself to CHECK it out. I Highly RECOMMENDED it !
http://www.motu.com/english/software/dp/body.html

- Scott