My iPod has stopped playing some files. Ok, lemme explain.

I completely formatted (Painfully slow using USB 1.x, since my mac didn't have all my new mp3's and was too lazy to go downstairs to format it) my iPod because I was completely reorganizing my iPod. I put all my music back on, and as I was going through my playlist, some of the songs don't play fully. Like, I'll select the song, it'll start playing. About 20-30 seconds into the song, the sound stops. The little bar that shows how far into the song you are, however, keeps on going. No sound. I've played the exact same files on my PC, and they play fine.

Other times, it completely skips songs. I'll select the song, and it stalls for a few seconds, then just skips to the next song.

I'm trying to think of problems. About a day before I formatted it I had dropped it. No more than two and a half feet, though. I did a hard drive check, it came back fine. I don't get it. Should I send it in for repair? I do have an extended warranty... But I don't want to part with my dear ipod for weeks :(