queenie - I think I have sized up in all that I have bought (I'm mostly S, but usually buy M here), BUT I tried on lots last weekend at N.Rack and there were some styles that looked better on me in my usual S size and some that I went looking for an L in. Sorry to possibly add any confusion.
For reference, I'm 5'5", and about 34B in bust, size S more often than M for tops.
tricia - don't worry, you've looked perfect in every one you've posted. . . now what about the ones we haven't seen yet