I do...I think without it I'd be lost nowadays. It provides me with access to all of my music in one place and I can pump it out through my floorstanding Mission speakers!
The great thing is, if you've never experienced Media Center edition of Windows XP, you can now take it for a test drive!
This is a funky swf which highlights the Media Center interface, if only there wasn't so much 'Not available in this demo' content, it would be a whole lot better mind... Check out the play slideshow option in My Pictures, which I use a lot to view all of my photographs whilst chillin' to tunes!