While I try to avoid travelling with a laptop, I do use a Powerbook as one of my workhorses and it sees some time on the bike with me when I shoot assigments on digital. You'll find it as capable as any out there, although it's a bit pricey. I assume you're fluent with Mac OS, if not, I'd probably search for a smaller machine in the PC realm. The huge advantage macs used to have when managing graphics has slowly diluted into nonexistence, unless you deal with prepress houses.
Bottom line: If you like it, go ahead. But a PC will do it too.
I strongly suggest you (and anyone reading this, for that matter) head for this link
to see Powerbooks and other digital wonder gear working through truly spectacular, demanding conditions. Great pics and interesting reading too.
[This message has been edited by Photog Rob (edited 25 March 2002).]