Missed draw: should I bet the river anyway?

[Nate tha' Great]

Party $5/10, 5-handed with an UTG poster (fine by me). I am in BB and have Q5 /images/graemlins/diamond.gif.

Poster checks preflop, CO and Button call and SB completes so everyone is involved in this hand.

The flop is a miraculous A /images/graemlins/diamond.gif 6 /images/graemlins/diamond.gif K /images/graemlins/diamond.gif giving me a nut-flush draw.

I bet out and get one caller, the CO.

Turn is a 6 /images/graemlins/spade.gif. I bet out again, called.

River is a 8 /images/graemlins/club.gif. I assume that my queen high isn't going to take it, and the pot is not insubstantial. Should I have bet out again?

[Nottom]

Honestly, you Q-high is the nut-pair of 6s so is beating most hands that would fold to a bet. It might be best to just check and hope for it to get checked through.