Calling a steal (?) river bet with middlepair top kicker?

[cyg]

Villian is 25/14. Here's the hand:
Stack sizes:
UTG: $35
cyg: $51.75
Button: $103.20
SB: $50.80
BB: $63.30

Pre-flop: (5 players) cyg is CO with A/images/graemlins/club.gif J/images/graemlins/club.gif
UTG folds, <font color="#cc0000">cyg raises to $2</font>, Button folds, SB calls, BB folds.

Flop: J/images/graemlins/heart.gif 6/images/graemlins/diamond.gif Q/images/graemlins/spade.gif ($4.5, 2 players)
SB checks, <font color="#cc0000">cyg bets $4</font>, SB calls.

Turn: 5/images/graemlins/diamond.gif ($12.5, 2 players)
SB checks, cyg checks.

River: 8/images/graemlins/heart.gif ($12.5, 2 players)
<font color="#cc0000">SB bets $10</font>, cyg calls.

Results:
Final pot: $32.5

My thoughts on him were that he either has nothing or the best he holds is a jack with either the same kicker as me or a weaker one.
Should I have folded the river instead?

[thac]

A lot of people play top pair like this. Check to the preflop raiser, call, check to him again on the turn. I don't like it. You might snap off a bluff sometimes but even the straight draw got there. I fold probably.

[Marshall28]

river IMO is an easy fold. also i think your flop bet was a little big. like 3.5 or even 3 accomplishes the same goal as 4 does here and saves us a lot of money in the long run. (however note that when out of position a larger bet is usually necessary). u pretty much only beat a pure bluff here. unless u know your opponent to be a habitual bluffer and u checked the turn in order to induce the bluff, you have no business calling here.

[cyg]

I usually fold there without hesitation, but something made me think he completly missed.
He was holding AKo, I certainly didn't put him on that hand though.