KQs -- huge draw in huge pot misses on river -- what's my play?

[Hoi Polloi]

All players are new to me but seem solid over 5 orbits or so. BB slightly loose and aggressive. CO tightest and most passive.

Party Poker 2/4 Hold'em (10 handed) converter

Preflop: Hero is UTG+2 with Q[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/spade.gif[/img].
UTG calls, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, <font color="#666666">1 fold</font>, MP2 calls, <font color="#666666">1 fold</font>, CO calls, <font color="#666666">2 folds</font>, BB calls, <font color="#CC3333">UTG 3-bets</font>, Hero calls, <font color="#CC3333">MP2 caps</font>, CO calls, BB calls, UTG calls, Hero calls.

Flop: (20.50 SB) T[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
BB checks, <font color="#CC3333">UTG bets</font>, <font color="#CC3333">Hero raises</font>, MP2 folds, CO calls, BB calls, UTG calls.

Turn: (14.25 BB) J[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG checks, <font color="#CC3333">Hero bets</font>, CO calls, BB calls, UTG calls.

River: (18.25 BB) 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG checks, Hero ???

Final Pot: 20.25 BB