You can rip files off of CDs in whatever format (mp3, AAC, and 2 or 3 other formats, I forget which)and play them on the ipod.
Itunes ONLY comes in AAC format.
If you have existing mp3 formats, it'll take them.
So, yes, I can play some of my mp3 files from my pc (converted from wma's to mp3's and THEN transfer them).
It's real frustrating with bruning the CD's, though, becuase I bought an CD mp3 player, but it won't recognize the AAC file extensions. . .I wish Alpine would've had that built in, I think AAC sounds a helluva lot better than wma's.
I think it's pretty versatile, I just don't like that I can't convert my AAC files to mp3's for my car CD player.