The quality of images taken by a camera phone depends heavily on the ambient light, u take pics in a sunny day with a K700i & still they will come out nice but if u take pics in a night environment with a N93 then still the pics will come dark
right now, as far as features are concerned, N93 beats any SE phone hands down, I m saying this just cos N93 has video recording at 352X288 & 640X480 resolution too, something even the K800i does not have, pity on Sony all the processing power of K800i is going unused
however, for still images, a K790i (which is same as K800i, just 3G features are added) beats N93 in 3 mp segment, however, N93 is better when taking pics of moving objects, & not to forget 3X optical zoom, it comes at a hefty price tag though
Shutter speed is less in both, when will these companies add features instead of adding mega pixels, which we don't even need over 2 mp for casual uses. A Mobile phone can never take the place of a digital camera
This is a pic taken by my K750i, in broad sunlight (flaunting my bike...lolz 
), it's RAW, without any Photoshop modification, at 2 megapixel
*img247.imageshack.us/img247/6687/bikefullct1.th.jpg
This is a pic of Wave Mall in lucknow, taken at Normal Size (640X480)
*img227.imageshack.us/img227/79/mallentryom3.th.jpg
As u can see, when reducing the image size, the camera has more pixels to squeeze in the 2nd pic, because of which it is much sharper then full 2 MP camera.
W810i is good, it has a new version of K750i camera & also comes with a Nvidia mobile video chip because of which the colors in that are better then K750i/N90/N91, also the exposure is better controlled
