Incredible, just incredible...
I still can't believe that we're discussing this...
1. People bring the "Killzone 2 hype" argument, seriously??? do you think Killzone 2 got real hype just because Vgchartz and other WEB sites were hyping it??? study a little of marketing and you'll know that TV is still #1 when it comes to advertising, also look at banners (not web banners, street banners, go outside to the real world), go to retail stores, and even look at really popular non-gaming web sites, do you still believe Killzone had hype?
2. People bring the "they're both FPS" argument, then i have to compare Halo with Wolfestein 3D, Doom, Quake, Half-Life, Goldeneye, Duke Nukem 3D, and even a Bungie title pre-Halo called MARATHON...
We can compare Bungie and MS with Carmack and Romero (and you know he's gonna make you his bitch XD ), we can compare Halo shooters with every FPS before and after Halo... And what do we get? nothing, it's simple people, Halo became the strongest FPS brand ever, and comparing their sales to any shooter besides Call of Duty is like comparing Mario sales to Little Big Planet's (and people did it, i swear) or comparing Final Fantasy sales to Persona's...
Do you know what would be interesting to compare? the day a shooter beats Halo, or the day a racer passes Gran Turismo, or the day a platformer beats Mario, or the day a JRPG passes Pokemon, or the day a life-simulator beats The Sims, or a sandbox game beats GTA (of course, i'm talking saleswise) why??? because the strongest brands are supposed to crash sales, so it's no surprise when they do... but when another game passes them??? that's real news... Until then, this comparisons are really pointless...