The biggest difference between those comparisons is the people at Microsoft, Apple, Real, etc have paid programmers whos sole job is to make a media player. Most open source apps (for the most part) are coded by hobbyist who work on it when they get a chance. It is kind of surprising that one of the Linux vendors hasn't put a little money into developing a media player. I'm not very picky so things like xmms, xine, and mplayer fit my needs just fine.
Originally posted by joshdick
Macs have iTunes, Windows has WMP, but Linux is lacking.