The 2.2 is a Santa Rosa MB, it can support 4 GB of RAM. The 2.16 is a pre Santa Rosa mother board, it supports up to 2 GB of RAM (3 in reality but you are supposed to put matching RAM chips in both slots for the best performance). I'd get the black one, it's what you want right? I think when you are talking about spending this kind of cash you better get what you want, it's not the type of thing you should settle on.
I've got a 2.0 GHz (black) I got it when 2.0 GHz was the top of the line, that was only in May. Believe me, with 2 GB of RAM in there it's unbelievably fast!
SLC
Wow, so 4GB must be like ridiculously fast, but the black one is what i want, and i think that if im spending a grand i should get the one that is most appealing to me.