I would definitely look at the Seat recommendations topic for some tips. If you are flying alone 10A and 10F are good in the 757. Lots of leg room and a window seat, but since there is no seat ahead of you, you can get up whenever you want. Otherwise row 9 is good or the exit row seats on the wing. If you get an exit row seat, make sure it is one that reclines, on some planes the first exit row seats don't recline all the way.

Neil