ubuntu 10.10 was released fully yesterday. i've been using it for a couple of weeks and it feels more robust than 10.04 did (i haven't had any issues with xorg failing to start thus far - and having to log in via cli then startx - with 10.10)
how familiar are you with linux at the moment..?
I think the Ubuntu distro might be the best if you don't want to stray too far from how XP looks and feels.
is that using gnome, kde, xfce or something else? any distro can run any of those. ubuntu comes with gnome by default, which looks and feels nothing like windows. you can install kde and use that, but then you might as well just download kubuntu instead (from kubuntu.org - it's ubuntu taliored for a kde interface). other window systems can be installed easily via the software centre.
Another good one would be Mint, which was based on Ubuntu but now looks to Debian.
ubuntu is built on debian itself.
http://www.ubuntu.com/community/ubuntu-and-debian