FWIW, I have one XP machine left, and havn’t used it in over a month. Everything I use runs on Vista (I don’t use Nero anymore, changed to the built-in burning software and a small fast ISO utility), and the media center is slick – so obviously my media center runs that.
Vista is more reliable, crashes less than XP ever did and those issues don’t take down the OS. Downside: requires alot of hardware.