For the couple of weeks a whole bunch of the songs from my iTunes library stop early and skip to the next song (just as if it was at the end of the song). Although the point where it skips varies for each song (for one song it is 2:32, another is 2:46), it will always skip at the same point for each song.
A while back I ran BPMer and, although it crashed half way through, it did not appear to corrupt my music the way it is now.
A few days ago I backed up my iTunes library and reformatted my hard drive (for a completely unrelated issue) and reinstalled OS X from scratch. The problem was happening before and after the reinstall.
This problem also persists when the music is synced across to my iPod touch running 3.0. Listening to the same troublesome songs in my iPod causes them to end prematurely. However, I can listen to the whole song using Quicklook, so the problem must be with my iTunes library or something.