A seat in line with (or "over") the wing is going to be the most stable part of the aircraft and, therefore, the most comfortable. If you're taller or feel like you'll be more comfortable being able to get out of your seat faster, you'll probably prefer an aisle seat. That said, if you're looking forward to viewing the world from on high, choose a window seat! If you're worried about crashing (you really shouldn't - it's crazy rare), get a seat towards the rear of the plane, as it's statistically the safest part of the plane in crashes.