As I wrote a few days ago, I got a new 2.4 GHz MacBook today. I think it offers the best combination of size & performance. It isn’t much bigger than a MacBook Air, yet it feels a bit snappier than my old MacBook Pro. The only drawback is the lack of FireWire, but all of my external drives are either USB 2.0 or dual interface.
I’ll post a more in depth review at MacMegasite.