I have been using the Casio EX-F1 Pro for a looong time now. The low resolution at 1200 fps is quite annoying, but it is the best I could afford.
I am constantly monitoring ebay for a better one, though - and today, I placed a bid.
See the ebay auction
I suggested a much lower price than the seller asked for - now he has 2 days time to accept or deny. Wish me luck!
Here is the camera specs - 4800 images per second at 800x600!
See the manufacturer specs (pdf)
I know this is a good camera, because it is almost the same model Destin brought a few months ago.