You have a bunch of good options. I just recently picked up a great little canon for $300. It had a great waterproof housing for an additional $100. One of the features I liked was the ability to zoom during the video. It takes SD cards.
I would shy away from Sony just becuase of the propriatary membery sticks.
Two other great ones I saw were from Fuji and Olympus. One of them had amazing color and ultra sharp focus. I think the fuji was the best in low light conditions.
Hope this helps
