100NL 6-max: Straight on paired river. Value bet or no?

[wax head]

Only notable hand I've had with villain, he hasn't been at the table long: It was a limped pot, 3 runners to the river with him OOP. He check called a 3/4 pot bet on the flop w mid pair A kicker (backdoor nut flush draw). Has a flush draw on the turn he check calls another 3/4 pot bet, hits his flush on the river and open pushes for about 3/4 pot (he started with half a buyin).

I had a hard time deciding whether to value bet this river or not. He thought for a bit before the flop and turn calls, and instachecked the river. No stats.

PokerStars No-Limit Hold'em, $1.00 BB (4 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

BB ($121)
UTG ($105)
Hero ($188.50)
SB ($125.25)

Preflop: Hero is Button with T[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/diamond.gif[/img].
UTG calls $1, <font color="#CC3333">Hero raises to $5</font>, <font color="#666666">1 fold</font>, BB calls $4, UTG folds.

Flop: ($11.50) Q[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $8</font>, BB calls $8.

Turn: ($27.50) A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $26.15</font>, BB calls $26.15.

River: ($79.80) A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, Hero ???