It really depends on the sys. requirements. With Crysis' speculated requriements, it looks like the 8600m will be able to run it well(probably medium settings), any possibly even the x1600 at low settings. Alot of times people don't even know that boot camp exists.
One would assume that now EA are releasing games for OSX, we can assume that they will release Crysis for OSX too. Of course, whether you actually want to run Crysis under OSX, when it is a no brainer that it will run 10 times better under XP or even better Vista for DX10 effects...
You won't want to run Crysis under anything but Boot Camp. Framerate comparisons between Vista, XP and OSX show that very clearly.
Unless Steve pulls out something amazing, like native, full speed DX10 support in Leopard... But that's not going to happen.
(Unless Cider allows programs to run just as fast as they would under XP/Vista, in which case we just need a DX10 Cider wrapper)
And the Santa Rosa Macbook Pro should run it quite nicely on moderate graphics settings.