This may be a VERY important decision, and one you may regret if you are used to a US keyboard.
Please see my recent post:
http://discussions.apple.com/thread.jspa?threadID=2332483&tstart=0
The bottom line is that on the european macbook they make room for the ` key by robbing you of half of the standard elongated shift key you get on a US keyboard. Consequently, stretching out with my little finger across this useless key has given me repetitive strain and I am one hurting unit at the moment.
What kind of idiots are these (the europeans I mean, and I am one of them!)? They put a key unused in most languages in one of the most useful locations on the keyboard, beside the 'Z'.