I recently got a ipod for my car,
I have always used Windows Media Player, and had about 100gigs of music saved as wma's
Itunes converted it, but really made a mess of the files,
Missing album art
Songs not put with the album they came from
(was always a greatest hits ablum. album with guest artest's, compalations)
Did I mention I hate apple?
I now run 2 seperate databases for my music, one for itunes and one for Windows Media Player. I copy new discs twice, due to the problems itunes putting album art and artist infor in correctly. I only run itunes to sync with my ipod, and i only got the ipod because kenwood interfaces with it using the touch screen on the indash head unit.
Sorry for the rant, but for me, Windows Media Center works Very well, there may be better programs, but for me, it just works. (win7 with the latest media center)