What would you do? #51 - Rivered top pair facing oversized raise against good regular

As I alluded to in earlier posts, I'm starting to take shots at $100NL. I want to establish that I can play that level. When I was ready to go up back in December, my bankroll was decimated due to the UIGEA enforcement that I thought was probably going to go into effect. However, I have since re-established a nicely-sized bankroll, and have started to take shots at the "big time." Here's an interesting hand that still has me thinking:

Sleekest is a good winning regular at these stakes, so getting mixed up in a pot with him is not my idea of a good time. I have a nominal amount of hands on him, but according to Will Wonka, he's a:
15/12/4.3 over 10K hands
36% Steal overall and 53 from button
74CBet
Folds to 3 bets 61%
Clearly, he's a TAG. Clearly, I need to get used to this type of aggression; I'm not seeing it at $50NL and I'm not quite sure how to handle it. How light should I be typically calling?

Full Tilt Poker $0.50/$1 Pot Limit Hold'em - 8 players
The Official DeucesCracked.com Hand History Converter

BB: $100.00
UTG: $40.20
UTG+1: $148.15
MP1: $152.70
MP2: $82.65
CO: $100.00
BTN: $63.20
Hero (SB): $166.20

Pre Flop: ($1.50) Hero is SB with 9d Jd
2 folds, MP1 raises to $3.50, 3 folds, Hero calls $3, 1 fold
I should probably have folded, but how can I fold J9s?

Flop: ($8.00) 6d 2d 7c (2 players)
Hero checks, MP1 checks
In position, with no cbet, he checks? Interesting...

Turn: ($8.00) 2h (2 players)
Hero bets $5, MP1 calls $5
Well, I have 2 diamonds and there's two diamonds on the board, so maybe I'll start to build a pot in the event I do hit. Additionally, I can potentially take this down right now. No dice, though.

River: ($18.00) Jc (2 players)
Hero bets $7, MP1 raises to $39, Hero folds
Good river. Sleekest has been completely passive in this hand and I honestly expect a call behind. He instead opts to overbet raise this pot. WTF? Anyone calling this? My thought is that I have $14 vested in this pot, and by calling another $32(!!!) is throwing good money after bad. Am I wrong? Should I be calling him light in this spot? I somewhat sense that he has a boat with this sized raise; hoping that I have an overpair or connected with the river. I'm confused by the fact that he did not bet the flop, though, with a lot of draws out there...

Opinions? Bad fold?

Final Pot: $32.00
MP1 wins $30.40
(Rake: $1.60)