[jcm4ccc]

Tough situation. I think the villian probably has a diamond and missed his hand. I think you should be willing to die with this hand. But how do you extract the most chips if you are ahead, or conversely save a few chips if you are dead?

I would check and call anything he bets, including an all-in. My reasoning is below:

If you have the villian beat:
He will probably fold to a value bet.
A check might induce a bluff (he is by far the chip leader).

If the villian has you beat:
He will probably put you all-in if you bet.
If you check, he may only value bet 100 or so chips to try to extract as much as possible.

BTW, I would have gone all-in on the turn. You had enough chips to make a pot sized bet