Try them out - LiveCD (Score 1)

An OS you like to use is influnced by many demensions beyond simple power. There are many liveCDs out there, pick up a few distros of Linux and try them out. That said xp is not too bad either. Just now I am using Ubuntu on my notebook. Prior to that I had Xubuntu and Wolvix installed. Have some fun and play around with it a bit. In the end you have to make up your own mind. Check out Wikipedia Linux overview. http://en.wikipedia.org/wiki/List_of_Linux_distributions