You'll have problems with ATI Mobility cards. Not that I have them, I'm having problems with Intel x4500 , but netkas' site and insanelymac are full of all sorts of questions regarding those.
Better choose a notebook with NVidia card, and check the usual forums for confirmed "success stories" about the graphics.
I've installed Snow Leopard on a desktop machine with i7, so that's working without any problems (Hazard distro).

Also, there are no kexts for Intel 5100 WiFi.