(.1 NL) Top set, family pot

[Ampelmann]

The typical $.1 NL Stars table. Many semi-loose players, a fair amount of min-raising, but also several legitimate bets. Some amount of preflop raising. A few tight players.

This is the first time at this table that I see 4 players coldcall a pfr.

PokerStars No-Limit Hold'em, $0.10 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP2 ($5)
MP3 ($9)
CO ($7.15)
Button ($12)
SB ($4.55)
BB ($13.65)
Hero ($21.30)
UTG+1 ($5.90)
MP1 ($6)

Preflop: Hero is UTG with A[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">Hero raises to $0.4</font>, <font color="#666666">1 fold</font>, MP1 calls $0.40, <font color="#666666">1 fold</font>, MP3 calls $0.40, <font color="#666666">2 folds</font>, SB calls $0.35, BB calls $0.30.

Flop: ($2) 4[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, BB checks, Hero ?

I have the best hand right now and I'm the big favorite for the hand. Maybe someone else has an A (which would be great), and a flush draw is likely given the amount of players. I don't want to lose everyone, but I don't want to give good odds to a flush draw (which it might get if several players call my bet). How much do you bet here?