Straight
 

Villain is 48/11/6 over 90 hands

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

UTG <font color="#A500AF">(Villain)</font> ($88.4)
Hero ($451.03)
CO ($87.5)
Button ($90.25)
SB ($245.9)
BB ($60.8)

Preflop: Hero is MP with K[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/heart.gif[/img]. SB posts a blind of $0.5.
<font color="#CC3333">UTG <font color="#A500AF">(Villain)</font> raises to $2</font>, Hero calls $2, <font color="#666666">3 folds</font>, BB calls $1.

Flop: ($6.50) T[img]/images/graemlins/club.gif[/img], Q[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, Villain checks, <font color="#CC3333">Hero bets $6</font>, BB folds, Villain calls $6.

Turn: ($18.50) J[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Villain checks, <font color="#CC3333">Hero bets $12</font>, Villain calls $12.

River: ($42.50) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Villain bets $25</font>, <font color="blue">Hero ???</font>

Re: Straight
 

I'm calling here, but I'm also usually folding this or re-raising preflop.

Also, any reads would be helpful. 90 hands isn't a lot, and his agression could just mean he's betting with the goods and folding when he doesn't have it. The fact that someone who is 6 times more likely to bet than call has check/called twice should set alarms off though.

Re: Straight
 

looks like a blocking bet with AA or a set, but with his stats it could be anything. obviously you're worried about AK, but i think it's more likely that he has two pair.

i'd call. you don't want to raise because he would just fold if you're beaten and reraise if he has AK...and you'd have to call a push.