it depends highly on what you prefer..
camera quality? wifi capability? design? etc.
n also, your budget.. by not stating those, forumers here can't help u to identify which is suitable for u..

well if camera is your main thing, u should really put n82 back into consideration.. n82 has the best camera quality from your choices..
next to it, i think it will be c902.. i've compared both g900 n c902 side by side before, n the picture taken by c902 is way more attractive compared to g900's.. the image colors looks way more richer in c902, while g900 images are really dull.. however, g900's screen width beats c902, as c902's screen is quite small..
so if u want both wifi capabilities and camera quality to be excellent, get a n82..

p/s: i'm also considering n82 vs g900.. still around here to check howz g900 since its new.. but one thing i find negative about g900 is the camera, the images captured are really bad for a 5mp standard..
but don't forget, one +1 point for g900 is the touch screen and its also newer compared to n82..