I would say go for the DC800!
A month ago I was in the exact same position as you, trying to choose between the DC800 and the DX-1G. I read up about the DX-1G camera, and the camera itself had gotten some mediocre reviews (as an above-water camera).. Of course, reviews are for guidelines and inputs, not decisions.
I guess what made me finally decide, was the price. I spoke to a lot of UW photographers at my dive trip yesterday, and they all praised the DC800. But the one thing they all said: The thing it all comes down to is the person behind the camera. Of course, the equipment really helps too.. but I would go as far as too say this: If you get the DC800 Pro Setup (with a strobe) and add the second one you've got.. you got a really impressive setup that is guaranteed to produce good photos!
As gustele pointed out, some divers/photographers want to be able to control everything. Me, I'm a sucker for automatic settings
Who knows, maybe that'll change as I progress. But during my first dive with the SeaLife DC800 yesterday.. I could just drift along, follow the fish around, dive into caves.. all this while looking through the LCD of the camera!
I hope this helped, and that I did not confuse you more!
EDIT: Right.. 5 months old thread.. Did not see that