I have had both an 800 and a 1000 and looking to go back to a Cannon SD model and an ikelite housing! That is what I would suggest. I have not been satisfied with the sea life. I have had allot of problems with the 800 and they finally just replaced it with a 1000 (factory). The 1000 has some issues or it is me? I use it and it takes great photos and the next dive I havent changed any settings and it is having flash problems or white outs and cant take a single good photo. The Cannon I had was much more user friendly. I would go for the ikelite housing for sure. I got one from cannon and it had leaking problems. Ikelite housings are allot better in my opinion.
Cannon 3" screen or some other user friendly camera and an Ikelite housing is next on my list of things to buy!