One of my computer related hobbies is building media center pc's.
When Windows Media Center 2005 came out, I obtained a copy via my MSDN subscription. Later, a friend was able to get me a media center remote control, and tonight I set it all up! This system is currently serving as a ReplayTV archive (thanks to DVArchive), and as a jukebox for my music and pictures.
Unfortunately, I can't get the video working yet, so no recording TV, but the music and picture functionality works great. It's a very polished interface.
Here's something you don't see very often: a 57 page license agreement! Of course, each page is quite short. And no, I didn't read it and just clicked "I Agree".
One nit I have is I can't figure out how Media Center chooses to order songs in a album. This particular song is sorted as last in the album, despite the fact it is track 5 on disc 2 - the song data and filename even reflect this. The songs are sorted properly by other media players...