[Robk]

I think the key point here is... what would your opponent do with top pair on the flop against a preflop raiser? Would he bet into you or check call all the way down? These are important things to know about your opponents, and many play this situation the same every time it comes up. If he would bet into me with a Q on the flop then checking the river is reasonable. If not, then I would bet the river every time.