Most realistic water rendering in game engines

[inlimbo]

Feel like Snake Eater deserve some special attention here. Not a ton of physically correct simulation under the hood, but there's painstaking attention to detail where water interacts with Snake, NPCs/wildlife and environment. You fire a gun underwater in Snake Eater and shell casings will eject and hang and float and collect near the gun, offset by buoyancy and friction in the water, before sinking to the bottom where they will remain indefinitely until you either leave the area or fire enough shots that one of the old casings is swapped out of memory for a new one. It's also got some of the best water bubble and spash particle effects i've ever seen. Especially the splashes, man.

http://www.youtube.com/watch?v=tBs6B48npoI&t=10m58s

Tomb Raider Legend (underwater, at least) and Tomb Raider Underworld are no slouches, either.

 

[Shaderhacker]

Here's an article about the water in Assassin's Creed 3.
http://www.fxguide.com/featured/assassins-creed-iii-the-tech-behind-or-beneath-the-action/

Creed 3 and Sleeping Dogs gets my vote for best surface shader on water.