Well, if we have shown anything, it is that calling this a no-brainer was probably a bit of a misnomer! [img]/images/graemlins/laugh.gif[/img]

This last method mentioned by Bruce is the one that I most frequently use during a hand, mostly because I find it easier to estimate the probability of winning and compare that to the ratio of my bet to total pot on the fly.

So, basically it comes down to whether or not you think there is a ~10% chance that villian has less than a straight in this case. I agree with Bluff in that most opponents would have check/raised with two pair on the flop. However, I have seen Villians line equal a naked 1 pair or 1 pair + weak draw on the flop and 2 pair on the turn enough for me to justify making the call against most opponents (facing a 2/3 pot all-in turn bet).