The current generation Canon's are very nice for this purpose. You can live without RAW with the fine setting for jpeg. Also DIGIC-II cpu is fast, and gives decent color and low noise, at a very attractive price.
Reasonable priced housings, basic underwater color correction (stills only). I also have an
Ixus 750, with the Canon case.
http://flickr.com/photos/robinslomko...ags/underwater <-- stills
<-- video
My girlfriend has an
A 620 (not sure what the European model number is)
It is a plastic body and larger. Exact same internal electronics, a physically bigger lense and it allows zoom while doing video. May be a little bit cheaper. It is just as good if not a little bit better as underwater Camera.
http://parts-unknown.com/gallery/april2006-reef_dive <-- stills from A620
I like my photos from Croatia better, but I think I got better at using the Camera, and the colder water was clearer.
I would purchase at least a 1GB SD card, I picked up a high-speed (133x) for 21 Euro here in Munich.