Suddenly my ipod mini doesn't show up in itunes. I have the latest version of itunes, and I just updated the ipod, but it still doesn't recognize it with either usb or firewire.
I have had this happen with both of my iPods on my powermac with the newest iTunes and iPod software. A restart and everything start working again.
This has happened to me a few times with my windows PC. I went through the list that Mad Jew suggested. I've never had to go past step 3.