I assume you're just referring to playing audio/video and not editing.
Right?

On the subject of editing, I've tinkered with Ubuntu Studio but whenever
I've posted a request for any type of support (here and the forums) it's
fallen on deaf ears. Over the weekend I did a fresh Windows XP Pro install
on half of a 40GB hard drive and a fresh 64 Studio install on the other
half. What I really liked about the install (after I got past a date issue)
was that it let me do a custom partition so I could separate /home from /usr
from /tmp & all that fun jazz. If anyone wants to check it ut go to
http://www.64studio.com/ and poke around. The stable version is 2.1 and
there's a 3.0 Alpha or Beta but I'm not one that likes to mess with Beta.