My 60 GB does the same thing. If I am listening to a continuously mixed album, it frequently pauses up to 3 seconds between tracks -- it's like the next track isn't being cached quickly enough, and the player is waiting for a disk to spin-up. This is a nuisace with the continuously mixed albums. This never happened with my 10 GB player, so I've kind of chalked it up to having 2 disks or something.

I have 26 GB of MP3s (4,400) so only one disk should be full.