The second villian would check and call with any medium or small pair, but he would bet strongly with flush/straight draws even on the turn. I though he could also be on a flush draw here.
The first villian almost always cheked and called when he was involved in the hand. So he must have had a strong hand here, but I called him down anyway.
I recently read the post by Ed Miller to call down marginal hands when the pot is already big, but I think I am doing it too often now:
http://forumserver.twoplustwo.com/showfl...rt=all&vc=1