I've researched this a lot, and the best 2 for $50 are the G9 and Razer Deathadder
However since u want for a 100, take a look at the Cyborg R.A.T series. Didn't come out yet, but it has everything you want in a mouse
I can say that I'm sticking with my Logitech G5 v.2
The only downside to the G5 is the wire, which gets worn down if the mouse is used on a rough surface - other than that it is pure pwness.
I know this is OffTopic, but have you tried Battlefield Bad Company 2? I used to LOVE COD4, really - but it feels like a game made 10 years ago if you've tried BFBC2.
Chris COD4 may have been made 10 years ago but damn its still a good game. I haven't actaully played BFBC2 but I don't want to because i've seen people play and it and take no offense but I don't think highly of it at all.
The two best gaming mice in my opinion are Logitech G5 or the Razer Deathadder. The G9 looks too uncomfortable to me, but it has great features.
The G5 has extra modifications to it such as weights and untangle-able wire, and Logitech is said to have better quality than Razer (Razer has had many problems with some of its mice, like the Lachesis)
If you search up "Best selling gaming mouse"in Google the Razer Deathadder appears