I'm not a big fan of slow playing myself. On lower limits, you rarely run into problems getting paid off (most of them think the only hand that you lead out with is top pair - you slow play everything else), and at the same time you protect your hand. I always play the nut str8 on a rainow flop fast, because if it gets checked around, there's a chance someone can pick up a flush draw or hit a gut shot to a higher nut - for example.
Say you have
[8c], and the flop comes
[9s][Td], and it gets checked around, then on the turn comes
-- congrats, you know have the sucker str8 and there is a heart draw.
However, with the hand you described, I'm assuming the player with the
[8d] is a bad player, and unless you could have gotten him to fold on the flop (unlikely), there is no way you would have gotten him to fold after he made two pair on the turn.
However on Saturday there was a hand I was very glad I slow played. It was a NL home game with $1/$2 blinds with an open buy-in. The table texture is pretty wild, there are a lot of loose action based players. I have one of the bigger stacks with around $450. There are about 6 limpers (uncommon at this table) and i'm in the small blind with
[5c] and I limp and the BB checks. The flop comes comes
[7s][Qh]. With no draws available I decide to check it. A player in early position bets $10 (probably betting the Q is my read), then a player in middle position goes all in for $120. This player "runs without the ball" a lot - and only bets that hard when he is weak post-flop. The player on the button thinks for a while and goes all-in for $200. This player is a pratical player. He would have raised with QQ, so I can eliminate that, He wouldn't have thought so long if he had A7s - thus he must have had either 76,87, or 79. I'm only ahead of one of those - and I'd need a 10,J,K or A to split the pot with him or a 5 to win. Not a good situation to be in. Thus - I folded. The initial better only had $20 left so he called. EP had AQ, the initial all-in player had K10o (WTF?) and the button had 79. The turn was a 3 and the river was a K. One of my better "slow-plays" even though I never put a chip into the pot after the flop. (and yes this is a juicy game)