...and I don't like it. This hand felt very wrong, but I don't know what I could have done different. I have no other read on the opponent other than that he is not horrible, which basically means he's not very loose nor a maniac. So, what could I have done different?

Party Poker No-Limit Hold'em, $ Hero (6 max, 5 handed) converter

Button ($204.30)
SB ($269)
Hero ($240.10)
UTG ($168.50)
MP ($191.60)

Preflop: Hero is BB with A[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/club.gif[/img]. SB posts a blind of $1.
UTG calls $2, <font color="#666666">1 fold</font>, Button calls $2, SB (poster) completes, Hero checks.

Flop: ($8) K[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">Hero bets $7</font>, UTG folds, Button folds, <font color="#CC3333">SB raises to $21</font>, Hero calls $14.

Turn: ($50) 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets $35</font>, Hero calls $35.

River: ($120) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets $60</font>, Hero calls $60.

Final Pot: $240

Dumle