Let's assume he is on his flush draw, and is a 30% favorite to win (not 36% because you your outs on a full house). Let's also add into the equation of a heads up or 3-way scenerio like this one where you hold 88 and flop comes 5s 8s Ks, and assume that one of your opponents hold the As.

Now, the way I play these hands is this: Aggressive. This is why: My first goal in Texas Hold'em is to find out when I am ahead by a good % margin, ASAP. When I am confident that I am leading in these numbers, I will hammer my opponents hard. It is a much more difficult decision about whether to stay in the hand or not when you opponent bets 1/4 pot when a 4th spade hits on the turn, or diamond in your case.

Find the easy decisions, and push them as hard as possible.

I came up with the 88 example from a heads up example in a live game lastnight, I pushed all in. I'd much rather win the flop pot than lose a river or turned pot.