1.If there was no halo then the xbox wouldn't have sold enough for MS to make the 360, and all fps games these days would be different because halo invented all the stuff like recharging health, 2 weapon limits, duel wielding and the fps control scheme on consoles.

2. And if there was no halo 2 then LIVE wouldn't have been successful and live and psn today would probably have less than half the users they have now.

3. Even if there was a 360 without halo 3 it would be in 3rd place and without reach the 360s lineup would fail this year

So it would change alot lol :)

The 360 would never have been around, and the xbox would have failed. Lets face it. Halo kept the xbox afloat for years. What a horrible world, where there was only the Wii and PS3 to choose from. Don't get me wrong, I own all 3 consoles, but my 360 is my favorite by far. :(

PC gaming probably wouldn't be effected much, but it would be likely for the console FPS market to have been far, FAR, less popular than it is today.