Ipod Christmas gift question.

My family and I do a gift exchange for Christmas – we each buy one gift of a certain price range (max $150.00) that would work for any of us, and then draw numbers. I’d like to get an Ipod as my gift, but I’ve never owned one and don’t know anything about them. I’m trying to figure out the basic difference between the Classic, the Mini, the Nano and the Shuffle. I don’t want to slog through the tons of technical info, I just want to know which would be a good gift. None of us are particularly technically gifted, so I don’t think I need video or any extras – just music. Thanks for your help!