Today i got my hands on d3100, and first impression is amazing - it can focus much faster than d5000, also in live mode. I didnt had much time with it, just 5 minutes before battery run out, so i couldnt even check out settings and so, but as a camera it has solid feel just like 550D. New 4 way joystick is much more comfortable to use than on d5000, on which it felt cheap and not so well made. Only bad thing about it is lens - they are just too huge to comfortable use, focus ring is quite good bud zoom ring is really big - kit needs better lens, 550D has a more comfortable zoom ring.
What i mostly like is new screen, and also viewfinder, which is (for me) better.
Some photos i managed to get - please, dont kill me i never shooted with DSLR, and this was just point and shoot on automatic and Apreture modes.
And if somebody wants video -
For me it is now better candidate than 550D.
I'm new to DSLR's, so please be patient and take my opinions with reserve. Thank you : ) Yes, i am Canon man. Google + My picasa photos My 500px album
Canon 60D + 15-85mm f3.5-5.6 IS, Canon 70-200 F2.8L
IS II, Canon 430EXII, polarizing filter 72mm,
Canon AT-1, 50mm FD F1.8