Epic Games has a decorated history for delivering highly visceral, quality shooters in the Unreal series that has seen several incarnations on the PC and console (despite a couple misses at the hands of other developers, *cough* Unreal 2 *cough*). However, despite their great successes, none have achieved such grand critical and commercial applause as what has come to be the 'killer app' of the Xbox 360, Gears of War. A Microsoft-exclusive game (a PC version has recently been announced), much of the 360's prosperity can be attributed to this game.
There a number of driving factors for the phenomenal commotion made about this particular title, not least of all the presentation - truly a showcase of the capability of the Unreal Engine 3 (which has been used in vast quantities of other current and upcoming games, thanks in part to GoW no doubt), but to flex the muscles of the 360. Your white console will throw around thousands upon thousands of highly-stylized polygons with relative ease, pit your band of soldiers against superbly detailed (and grotesque) foes, and will see you explore wonderfully delineated, if however linear game environments. The art direction of the game is gritty low-tech, sci-fi (I'm not sure if that even exists), set on a desolate wasteland of a planet dubbed Sera - the charred ruins, dark forsaken roads and forsaken edifices make conveniently cool battlezones.
The plot driving this masterpiece is indicative of a distinct focus on action, action, and more action - that is to say, the story is crap to null. Pardon me for trashing the lack of motivation and/or backstory, but it appears to the player that you've been thrust into a situation that is missing a lot of density (though this is not atypical of the genre), and the cutscenes do little to fill you in. Despite this, in fact, almost because of this, the game is superb on the grounds of its tight, challenging and frenetic frays. In lieu of intricately woven emotional setpieces that set the heart aflutter, this game instead gives you an assault rifle with a chainsaw on it that can rend your Locust nemesis' flesh in twain.
My opinion of the game can be expressed in three words: buy.it.now.