Every camera phone I have used indoors has produced the same photograph: a grey smear of a face, lit by an LED that turns skin the colour of a hospital corridor. The K790 is the first one where that stops, and the reason has almost nothing to do with the number Sony Ericsson is putting on the box.
It has a xenon flash. An actual one, the kind that fires a short bright burst rather than switching on a torch and hoping. That single component does more for the pictures coming off this phone than the jump to 3.2 megapixels does, and it is going to be mentioned roughly a tenth as often, because megapixels fit on a shelf label and flash technology does not.
I want to be blunt about the megapixel thing while we are here. Going from 2 to 3.2 on a sensor this size buys you very little that you can see, and past a certain point it actively costs you, because the photosites get smaller and the noise gets worse in exactly the low light conditions where phone cameras were already failing. The industry has settled on the one specification that is easiest to print and hardest to defend, and I expect it to keep climbing for years after it stops meaning anything.
Sony Ericsson has also done the unglamorous work: autofocus that settles in a sensible amount of time, a lens cover that makes the thing feel like a camera when you open it, and BestPic, which fires a burst around the moment you press so you can pick the frame where nobody blinked. That last one is the feature I have found myself actually using, which is not what I expected when I read about it.
The choice worth thinking about is that this is the version without 3G. Sony Ericsson is selling the same camera in a UMTS body for more money, and if you are on a network where 3G coverage is still a map with holes in it, the EDGE version is the sensible purchase and the battery lasts longer. I suspect most people will buy the more expensive one anyway and use the 3G radio for almost nothing.
Where this stops being interesting is the moment you want to do anything with the photographs. Getting them off the phone is still miserable, and no amount of xenon fixes that.