I don't really want to install Windows on my iMac. I've already had too many problems with it and I don't want it wasting my HD space! It would be nice to see Crysis for Mac but that will never happen. Luckily, I've heard some news about the Crysis engine on the PS3. That would be nice.
Played it on my parent's first gen Core Duo iMac. Ran ok on medium settings. Looking forward to playing it on my MacBook Pro when the new ones come out. I've also played it on my girlfriend's comp with a 8800GT I put in.
With the ATI x1900 playing in XP I get around 20FPS with all settings on high, no anti aliasing, and medium resolution. It looks very good nonetheless.