re: Poker & [100nl FR] Top set...
If he's just drawing, we can make a good decision on the turn. Giving up in a small pot when there's four to a flush and our opponent makes a pot-sized bet on the turn is not a major decision. If the turn bricks and he leads into us, we can charge a very good price for him calling.
That said, against a passive opponent (which seems to be what we have here) raising is probably the better play. When a passive player leads out, he's not bluffing
very often which means that he either has a hand that's close to drawing dead, or he has us crushed.
Using some very leet PokerStove tricks (HAX!), it seems there are about 10-15 combos of hands that he flopped a flush with, if we give him the somewhat wide range of 25%. Let's say 12.
Flush: 12 combos,
Sets: 6 combos,
Two pair: AT(3), A3 (3).
Against a flush, we're 33% to win. Against TT, we're 93%. We lose a smidgen of value by raising from preventing him from bluffing the turn, but that's vastly overshadowed by the fact that he's not folding anything in his range when we raise the flop.
The reason I bring up the initial flop raise is because I think that's the more interesting decision in the hand.