A55 Second Lens. Please Advise SAL35F18 SAL50F18 SAL55200-2

Best single lens is the nifty fifty. If I had $300, however, I'd get the above pair.

50mm is a bit short for portraits. SAL85F28 is a good portrait lens. Used Minolta 135mm f/2.8 is even better (just for the beautiful photos that come out of that one).

50mm is a little long for action and baby shots. 35mm is better.