Err.. I don't know what iPod you have, but my advice would be simply to format it (or reset, have to look into my iPod to know what it says exactly), and then all the double ones should be gone after you've synchronised it again... But when you've got a 60G one filled to the top, that would take rather long I guess
Or something else: It might be you have some slight differences in how you've written the album titles (extra space, capitals, ...) Best way to solve that is to get a tag editor (like
mp3tag) and get them all right... Terrible job, takes an awful lot of time (depending on how much mp3s you have, obviously), but it's worth it, methinks...
Owh, and don't forget to give the apple site a look if there aren't any updates for your iPod software (or is that firmware

), if so, you just have to plug it in and open the iPod updater program to update it then (after downloading the new version)...