Ipod nano 3g question?

I have an ipod nano 3g (4gb) and when I go to sync. my music and stuff I keep seeing something weird. Everything syncs. over but it says that .43gb of the ipod is being taken up by "other", so not music, video, photos or games. I don't know what this "other" is because I already took all my music, videos, etc. off but it's not that. What could it be?