If United were so good how come you lost 2-0 - at home? I seem to remember the papers going on about that game as evidence of a power shift, if anything Arsenal were by far the better team! United were the better team in the final, granted, but only because Henry was missing and you still couldn't score or win on penalties.
So all the omens are good for Arsenal, since we won our last game against United in the FA cup as well as the last FA cup and league game at OT!