How to best be aggressive here?

Table is unusually loose and passive, even for 0.10/0.20.

PokerStars 0.10/0.20 Hold'em (10 handed)

Preflop: Hero is BB with A[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, <font color="#CC3333">UTG+2 limps, MP calls, MP+1 calls</font>, <font color="#666666">2 folds</font>, <font color="#CC3333">Button calls, SB completes, pdxhero raises, </font>, All Call.

Flop: (12 SB) K[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(6 players)</font>
<font color="#CC3333">SB checks,</font> Hero ... ?

The question is: bet out or try and checkraise? If I bet, nobody with a diamond will be folding before the river. If I try to checkraise it might be a little better, but with the passive table and the tendency to check to the raiser, there is big danger of giving a free card.

Any other choices?