I would say Gears of War 1 was a big step foward in terms of gameplay, graphics etc the story was lacking but I think it was the most innovative.
Might be a stupid answer but SuperMario Galaxy was pretty incredible also with graphics that pushed the Wii and some truly amazing gameplay and innovative stages, that game was awsome.

Spore.

Procedural generation is the way of the future.

All games will use it eventually.

Left 4 Dead comes close too...

as will Borderlands.

Anything using procedural though is doing a lot more then most games.

Wii Motion + games will be around that level too i guess.

PC - Crysis, Spore
HD Console - MGS4, Uncharted, Gears 2, GTA4

OK does this include PC titles?

To me it's kind of hard to really pick a game in certain respects.

I.E. I think the biggest achievement lately is the AEGIS(or is it AEGIA or whatever) Physics engine which I first saw in City of Heroes and I do believe is used by 2K in games such as Bioshock and Prey. I could be wrong, you librarians out there can verefy this stuff, Iand I thank you in advance.

To me this is a huge breakthrough not only in graphics/aesthetic appeal, but in gameplay as well. There seems to always be some kind of neat or odd thing that my wife and I will see whenever I play Bioshock where we say "Wow haven't seen that one yet".

Considering the vast majority of these major titles lease large amounts of code, I believe it can become trivial on who exaclty to tribute with this kind of an accolade.

Yet, you probably weren't trying to look that deep into it, and just want a general what game.

I would go with Fable II. It pushes the 360 hard. Too hard in fact, where it becomes glitchy. The physics engine is good, not quite Top rate, but it definatly is there. I belive most of their code is in-house so that is a notable achievement there. The art direction in the game is also additionally stunning as well as the graphics, so it makes it aesthetically more pleasing in that reguard. That opening cinematic, with the bird, is definatly the best I have seen. Another fact that you can see all the "veins" on the leaves and every detail is loaded on the map (I think it compresses/depresses per frame, not sure though) and you can see the whole area of play in the "field" definatly makes the box work hard.

I really can't think of any other game that has pushed so hard graphically.
I have not seen/played GTAIV. If someone says Star Wars, they deserved to be smacked.

For consoles? Metal Gear Solid 4 is the King on its Throne.

For PC? Crysis by a longshot.

great topic- i have 3
Gears of war 2, graphics are superb
Resistance, all out chaos, tons of actions on screen at once without a framerate drop.
mgs4- all out best for pushing the envelope an story, graphics, and fun game play.

Hopefully killzone2 will take the aspects from all of these and become the best yet.

 +1

 I think it has to do with the duribility of the disc more/less.  Like spinning for x amount of hours is like x% of wear and tear or something.  I'm not sure on the science of it but I can tell you that my NHL Hitz 2003 for gamecube practically doesn't play any longer, since between my friends and i (mostly friends) played well over 5,000 (not a typo) games on it.

hate it or like it, it has to be Spore.

NJ5 that is absured, designers are saying that no console have ever been pushed to its limits.  The ps2 was suposedly only using 75% of its power.  And Guerrilla owner said even with there technicological achievements on the ps3 they haven't come close to harnessing all the power.  

Yes i think that many publisher bite of more than they can chew, but im am always game for developers to push consoles.