When to call an obvious value bet

[Ryan2009]

25 NL

First orbit at the table but Villain already showed down trash.

Getting 4.67:1 on the river bet. Should you usually be calling this down given the action and board? The flop bet and turn check seemed to me like a made hand and I don't think he plays draws this way.
Pacific Poker
No Limit Holdem Ring game
Blinds: $0.12/$0.25
5 players
Converter (http://www.neildewhurst.com/hand-converter)

Pre-flop: (5 players) Hero is Button with K/images/graemlins/club.gif K/images/graemlins/heart.gif
UTG calls, CO calls, <font color="#cc0000">Hero raises to $1.25</font>, 2 folds, UTG calls, CO folds.

Flop: 3/images/graemlins/heart.gif 4/images/graemlins/heart.gif 5/images/graemlins/club.gif ($3.12, 2 players)
<font color="#cc0000">UTG bets $1</font>, <font color="#cc0000">Hero raises to $4</font>, UTG calls.

Turn: 2/images/graemlins/heart.gif ($11.12, 2 players)
UTG checks, Hero checks.

River: 7/images/graemlins/club.gif ($11.12, 2 players)
<font color="#cc0000">UTG bets $3</font>, Hero ???

[Vyse]

Wow, what a joke. Calling is mainly for info and table image -- showing down a good hand is always cool. I'd probably call, but yeah, it's obvious you're beat.

[cuQa]

I would call.. often enough you'll see just 2 cards