100NL- straight on paired board

[traz]

Villain is 16/10/2 over 125 hands. I didn't raise the flop at first because I felt like I would definitely get an overcall or a raise...dunno, not typical for me, but that's how I went with it. Given that...what's the turn play?

Party Poker - No Limit Hold'em Cash Game - $0.50/$1 Blinds - 6 Players - (LegoPoker Hand History Converter)

SB: $75.32
Hero (BB): $100.00
UTG: $141.81
MP: $250.80
CO: $263.58
BTN: $90.80

Preflop: Hero is dealt 4[img]/images/graemlins/heart.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] (6 Players)
UTG folds, MP calls $1.00, CO folds, BTN calls $1.00, SB calls $0.50, Hero checks

Flop: ($4) 6[img]/images/graemlins/diamond.gif[/img] 8[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/spade.gif[/img] (4 Players)
<font color="red">SB bets $2.00</font>, Hero calls $2.00, MP folds, <font color="red">BTN raises to $7.00</font>, SB folds, <font color="red">Hero raises to $20.00</font>, BTN calls $13.00

Turn: ($46) 8[img]/images/graemlins/diamond.gif[/img] (2 Players)
Hero checks, <font color="red">BTN bets $28.00</font>, Hero folds?