Get the best cpu you can afford even a 2400 athlon xp like i have in my pc is very cheap now for best results stick to the basics nvidia graphics card creative sound card most other pc software work best with these no reason why the radeon would not work just as well .
windows 2000 is more stable than xp i have not had to reinstall for more than a year on my heavily used machine where freinds and family have nothing but trouble and crashes with xp i have never seen a blue screen of death in 2000 but have seen it a few times in xp. :-)