did i misplay this AA?

[authority11]

Party Poker No-Limit Hold'em, $2 BB (9 handed) converter

MP2 ($200)
MP3 ($198)
CO ($182.03)
Button ($136.8)
SB ($234.52)
BB ($173.22)
UTG ($114)
Hero ($520.45)
MP1 ($211)

Preflop: Hero is UTG+1 with A[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/club.gif[/img]. MP2 posts a blind of $2.
UTG calls $2, <font color="#CC3333">Hero raises to $8</font>, <font color="#666666">3 folds</font>, CO calls $8, Button calls $8, <font color="#666666">1 fold</font>, BB calls $6, UTG folds.

Flop: ($37) T[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, <font color="#CC3333">Hero bets $20</font>, <font color="#CC3333">CO raises to $174.03 (All-In)</font>, Button folds, BB folds, Hero ???.

Should I have made it 5x BB to preflop? What about the flop bet? What hand do you think he had? I hadn't seen much out of the ordinary in his betting style until this. Seemed pretty average all around. Results in a bit.