Call of Duty 4: Modern Warfare
Been doing mostly the singleplayer campaign and a little multiplayer on the side. In short, the singleplayer is probably one of the most fun I've been through with an FPS. While the story/locations/enemies seem cliche now, it's the way that it just throws you into all this action and doesn't stop or really slow down(even the slower parts are fun), plus how challenging the AI is and the fact that combat relies on just as much cover and formation tactics as it does firepower really keeps you on your toes.
Multiplayer's pretty fun too, and I can see why this game got so popular. Not sure if I'll play through any of the ones that came after this, but man is this fun.
Also, been playing
Mark of The Ninja
Probably one of the best stealth games out there. You'd think that a genre like stealth wouldn't work with a 2D platformer, but the way the controls are laid out and feel as well as the design decisions in terms of showing enemies' cones of view and visually representing sound within the game are remarkable and pretty ingenious.
Some people might think that this dumbs down stealth gaming, but if anything it's alot more accessible and revitalizes a genre that doesn't always get the respect it deserves.
and been powering through
Red Dead Redemption
It's almost unbelievably good. If you haven't checked it out yet then I highly suggest you do, it's probably one of the biggest gaming landmarks of this last generation.