I've taken that flight recently, actually found Seatguru to be quite accurate on the AA777. My personal pick would be 1) bulkheads 2) exits 3) 41C or 41G.

Be aware that bulkheads on this flight seems to always mean crying babies. I started upgrading to J using mileage/copay partially due to this exact reason. If you have the miles and cash, I highly suggest it.