Another Mac user here. Been using 'em since '89. I've worked as a graphic designer (mostly print) for the last 12 years so my Macs have been my babies. Haven't actually made the full jump to 0S X yet, mainly 'cause 9.2 still does everything I need and the combination of hardware and software upgrades has made the price pretty steep. I did just return to school recently, though, so the educational discounts bring the price down quite a bit. I'm hoping I'll be able to make the jump soon.
Umm, in addition to my regular work, my Mac has been used for all the work I've done for the Privateer Press guys (monsternomicon, character sheets, lock & load, & warmachine prime), so that's probably it's best rpg connection for me.