I have a 4th gen 20 GB ipod, which started to have long delays when starting or skipping songs. Then I got the folder with a ! thing. Hard reset, still no good. Restored the ipod and tried to update songs again. Goes for a while and then the ipod locks up(after 100-200 songs). Gets stuck on a song for quite a while, sometimes getting past it, sometimes locking up. Copies quickly for most songs. Sometimes Windows will report a delay write error. In this case, the ipod typically cannot be ejected either from itunes or Windows. The 'do not disconnect" does not go off, so I have to either just unplug it or reset. Disk makes lots of noise. If I can update and it doesn't lock up(with only 50-100 songs), it seems to work OK. Tried restoring several times with the same behaviour. Takes a long time to recover from a hard reset. Tried with 2 computers, front and back USB ports. I also have an ipod photo 30 GB(really nice unit) and an Ipod 4 GB mini with no problems. I'm a little concerned that when I send it in for repair that apple will simply restore and load a few songs, and call it good, charging me for diagnosis.

Another topic: if I send it in for warranty repair, can I still buy the extended warranty for the returned one?