I was considering using Bootcamp, but decided to try parallels first.
XP boots quicker in parallels than it does on my work IBM ThinkPad P4M 2.2ghz, 1gb RAM etc and thats with out 512mb ram assigned to that VM.
I've literally just finished intalling ubuntu linux into another VM as well.
All is very painless and easy to do.
Fantastic piece of software.