In my opinion Milf is right you are wrong. Halo was exceptionally well executed the fact that it comes along a good few years before Half-life 2 proves another thing, Milf was right when he said any half decent fps since halo has borrowed heavily from it, Half-life 2 borrowed from Halo, then again it admitted the borrowing most designers would be a fool not to say "hey we saw that this game is loved so we tried looking at what makes it loved and work something out for our game to hopefully give it the same desirability." As for AI in halo, did you even try Legendary? it was insanely difficult. I loved the challenge of it and the AI was pretty intelligent for the time, how many times did you get a new fps out the box and see enemy troops run blindly in to the grenade you threw not caring that in ohhh...*booom* seconds the grenade will explode killing them prior to Halo? Quite a lot of it actually. Halo also made it fun to play FPS games it wasn't like the awful rendition of quake 3 on PS2 where you just fought bots in the levels. It was beautiful I still play Halo 1 and Halo 2 and will definitely buy a 360 for 3 even if it's the only game I want for it.
Personally I am going to agree with Milf again on Half life series being overrated. I found it dull mind destroyingly dull. I loved Counterstrike when I used to play it but even that got taken over by people who saw it for more than just a bit of fun. I tried to complete Half-life 1 and failed completely not 'cause I couldn't do it, that wasn't the problem it was because I couldn't find the will to beat it I was so bored.
Another genre of overrated games in my eyes is wrestling games, they're games based around fat greasy men in speedos grappling with each other in what can only be described as an all too homo erotic way. Each one is repeated every year with the same dumb moves in it in the same dumb button sequence the only difference is the speedos change by a half tone of colour. The story lines suck and just why? Ok so maybe I dislike wrestling and football and could sit here bashing away at them both for hours if not days on end but still. It doesn't need to have a new wrestling game out every year and the fact that there is more than one each year is simply blatant money grabbing, they know people are dumb enough to buy it even if there is no changes from the last one they'll buy it because the box changed colour.