[bmxreed36]

First off, I'd bet the flop.
By the river, I'd put him on either a set (7's?) or the Ac with maybe a pair, not many two pair hands are likely.
Most one pair hands are not going to pay you off anything. A missed flush draw is not going to pay you off anything. However people can't fold sets so I just push--its not a real awkward bet (slightly more than pot) and people automatically like to think those type of bets are bluffs.

Edit: Looks like the words were already taken out of my mouth.