I would definitely get a MiniDV camcorder. That's the format iMovie edits. I have a Sony TR17 that is about two years old. I'm sure the model is obsolete but I have had great luck with Sony digital imaging products. I like the Memory Stick format for stills. I travel with a powerbook, the cam corder and a Cybershot. That means in the evening I can download both pictures and video and have the media ready to go for the next day.
Definitely go and try out whatever you are thinking of buying. How it fits in your hand makes a big difference. If I had to do it over, I would get one of the very small/palm size digital videocams. I have a larger one and the one thing I don't like is that it gets heavy to lug around all day.