The newest and "hottest" game that I can think of which has truly got me drooling is Far Cry 2.
This one has been built on the Dunia Engine, which is coming to X360, PS3, and most importantly (

), PC. It will be released sometime this year, no offical news yet.
The new setting is in Africa, which combines rich jungle with tropical desert. The AI is said to be fully free, virtually meaning they almost live lives. However, seen as that technology doesnt really exist, many are saying that there are thousands of actions put into FC2 which tell each character to do a certain action at a certain time, which means they give the impression of a true life cycle. For example, soldiers will sleep at night, and can pick up nearby objects to use as weapons. Fairly impressive.
The first video of the new engine, is
this. It showcases painfully little, yet the grass and wind effect look superb.
The best way to get a taster for the game is
this video. This is a pre alpha build, yet the game already is in a very playable state, even way back in August.
The best thing about the FC2 engine seems to be the weather. A video showing a storm, and other weather implements, can be found
here.
The game also offers a hanglider, making it easy to get across the map. It is yet to be seen in action, as the pre alpha build did not have it included. The vehicle system looks similar to Crysis, switching between positions seems easy and quick.
The engine also uses a new process which allows trees to grow back after being shot down or burnt, allowing the game to adapt to the environment. Again, although this may seem advanced on the outside, it may be quite primitive in coding respects, and may show us where games are heading in the future. A video of the process can be found
here,
here, and
here.
And that is why Far Cry 2 is my most wanted game, which is both new, and "hot".