Paying off on the river

Pacific Poker, 2/4, no reads

Preflop: Hero is MP3 with A [img]/images/graemlins/club.gif[/img],K [img]/images/graemlins/diamond.gif[/img]
Everybody folds to me, I raise, 2 folds, the blinds call, and the rest folds.

Flop: (6 SB) T [img]/images/graemlins/club.gif[/img],2 [img]/images/graemlins/heart.gif[/img],K [img]/images/graemlins/heart.gif[/img] (3 players)
Blinds check, I bet, both blinds call.

Turn: (4,5 BB) 9 [img]/images/graemlins/club.gif[/img] (3 players)
Blinds check, I bet, SB call, BB folds.

River: (6,5 BB) 5 [img]/images/graemlins/heart.gif[/img] (2 players)
SB check, I bet, SB raises

Should I call here? I know I reveal the results now, but it doesn't matter really: I called here and lost to a flush.

It was of course very obvious to me that I was beat and I have mostly been folding that kind of hands until now; based solely on the chances of him having a weaker hand than me, this is a clear fold I believe with the pot laying me "only" 9:1. The reason I ask this now is because I've been criticized (by myself mostly) about my high 'Won$AtSD%', it's slightly above 60%; I'm probably not paying off on the river as much as I should.

With no reads it was an obvious bet for me, he could have been calling all the way with many hands. But then he check-raised me, is it TOO obvious that I'm beat here that I just have to fold, or is it ok to pay off just for advertising purposes; perhaps to stop possible future bluff attempts?

If I did have a read on him, would it matter? No matter who my opponent is, and looking at how the hand was played, a check-raise bluff is very unlikely. Should I tend to call more in that spot with a tough opponent to stop him from making tricky plays on me in the future, or should I tend to call more with a weaker opponent because he would check-raise with weaker hands in that situation? Or is it just a fold?

Sorry for this somewhat lengthy post. Perhaps this is simple questions, but not for me. This is a part of my game that I want to improve, and I would appreciate your thoughts on this. If you don't think this hand illustrates the point, feel free to give your thoughts in general about paying off on the river.