They kissed once--Peggy pulled Steve toward her and planted a great one on him just before he was supposed to jump onto the Red Skull's plane. I think Cap/Peggy works so well because of the chemistry of the actors, because Peggy wasn't forced into some typical "girl in jeopardy" plot (which has been the weakness of all the Spider-man movies) and because Hayley Atwell is just awesome.
The best thing The Winter Soldier did for Cap going forward was to "Jason Bourne-ize" his fighting style. I think that immediately made Cap cool for all the folks out there who weren't quite convinced by his first movie. I have to admit, even though I loved the first movie, the new, ultra-confident, ultra-badass, runs-straight-through-walls-when-he's-chasing-someone Cap we got in the second movie was a revelation.