I've heard people claim "Vehicles, Halo brought vehicles to FPS" and that's bullshit there.
It brought free-roaming ground vehicles, which was a pretty big step forward from the rail-driven ones of olde.
The only thing I could possibly think of is Co-Op mode, I can't think of a game before it that had that. And that's an awesome thing, I'll give it that.
Uh, Doom had Co-Op. I'd say Halo 1's biggest innovation was an intuitive and fluid console FPS control scheme. One thats been mirrored many times.
By the way, how is Halo 3 the most innovative game of 2008? It came out in 2007 >.> 2008 isn't even fucking over..
And Fiscal Years aren't January-December either, so why don't you bitch out corporations too?