4-handed vs. UltraLAG

Situation:

$20 buyin NL, .25/50 blinds... down to 4 players

Hero has about $25
Villain has about $40

Villain is very very aggressive. Knows I'm tight, and for weeks has been coming over the top of my bets in attempts to buy the pot. Often caught bluffing with nothing.

Hero is on the button, and dealt: K[img]/images/graemlins/diamond.gif[/img]8[img]/images/graemlins/diamond.gif[/img]
2 people call
Hero raises to $1.50
other 2 fold
Villain reraises to $3
Hero calls.

Flop: ($5 or so)

K[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/spade.gif[/img] 2[img]/images/graemlins/spade.gif[/img]
Hero leads for $5
Villain raises to $10

Hero ???

Notes on villain:
- will re-raise preflop with anything from 99-AA, but will usually try to slow play huge hands (QQ-AA)
- will always just call with low pockets (that I've seen in playing with him for months)
- will re-raise with hands as weak as AJo
- will bluff any suited flop with a big raise against tight players

With these notes in mind, I figure he has something like AQ,AJ,AT, AA,QQ,JJ,TT,99 , possibly 2 spades

Holding the King, despite the crappy kicker, I decided to push here to keep out any of his flush draws or draws to the ace.

Thoughts?