XBMC was the best for DVD movies, but since 9.03 that program took a dive... In Linux there is no pure Debian release it is a Ubuntu mashup and does not work well outside of a Ubuntu Box... Sad day XBMC chose to make it almost a closed for package for one Linux Distro...
SMPlayer is great in WinXP & Linux. A front end for Mplayer and this is the best way to install this jack or all trades video software...
VLC, there are many features that are not well documented about this amazing software, some users call it light weight software, but if you take the time to search out the tools you will discover it is multifaceted software...
Amarok, and Kaffeen are the two music players, I was using Songbird, but the Linux support seemed to disappear in a Microsoft operating system this software is still OK.. Atunes works decently in the Microsoft arena, but needs better functionality for Linux use...