All of my iDevices get stuck in restore... WTF?

It seems that every time that I try to update or restore an iDevice on my mac, it gets stuck a bit more that half way through the process. I have tried reinstalling iTunes, updating it, and using different iDevices, but the results are always the same. My iPhone 4 is currently stuck updating to iOS 4.1. The only thing that works is updating it on a friend's computer. What is going on here? Thanks in advance.

 

Yeah. I can't seem to do anything. You'd think that reinstalling iTunes would do it.