I currently have a 13" MacBook Pro, which I love. I had the same debate when I bought the MacBook this summer. I had the same issues as the above: no camera, no USB port were the biggies for me.
Rumors about the iPad 2.0 coming out after the first of the year (April?). It will have two cameras (forward and rear), Facetime, and a USB port. If that is the case, I will certainly buy one of these as it will accomplish 99% of what I need to do on the road. If I have to use BidX or do any other computing, then I will take the MacBook.
Just my $.02
Haz