River Missed Everything - Triple Barrel it anyway?

[DoubleTwentyOne]

$2/5 at Venetian
Effective stacks $600
Hero - TAG image
Villain - likes to portray a LAG image although everything points to him playing more like a TAG post flop

Hero limps with A [img]/images/graemlins/club.gif[/img]7 [img]/images/graemlins/club.gif[/img] in MP, villain limps on the CO, two more players in.

Flop ($20): 8 [img]/images/graemlins/club.gif[/img]5 [img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/club.gif[/img]
BB checks, Hero bets $20, villain calls, rest fold.

Turn ($60): 9 [img]/images/graemlins/heart.gif[/img]
Hero bets $50, villains insta-calls.

River ($160): 7 [img]/images/graemlins/spade.gif[/img]
Hero bets $150...

I thought river was a good card to bet anyway. Someone tell me I'm not spewing...