I like row 3 on the grounds that it is a little further back in the cabin and accordingly there is less traffic approaching your seat from behind.

Note that the 'A' seat on the left hand side has the advantage that you can stow your sideplate on the side table without offsetting your main plate. In the 'K' seats on the other hand you may find that if you wish to have a sideplate on the left the main plate may be offset slightly.