What do I do here?

[Psycho21]

5-10 no limit in Tunica right before the WPT in December.
I have been playing in this game all night and have about 2k. Pretty sure the guys I who are paying attention see me as weak a player because I haven't done much in the game, except for a couple of pots where I hit a monster flop and got paid off. I have not seen the villain make a bluff of any real size all night, he seemed to be a good player, however, before he started in on the Vodka.
Villain raises utg to 50. I go 150 with blk kings. He calls.
Flop is Qxx all spades. He bets $300 I go to $800 and he thinks for a little while and pushes.
Comments on anything are welcome, but I am more interested in whether I should have just smooth called the flop.