If you are a true hardcore gamer, and you consider yourself someone who will aquire the latest bit of kit to attain the best possible performance from yourself...sparing NO cost, the only mouse i would recommend it the razer boomslang (http://www.razerzone.com)
pardon the "blatant" advertising there, but its a TRULY superior mouse, smooth at ANY sensitivity on USB..and far smoother than my slow Intellimouse exploder...have you ever been shot in the back a few times...and had to make several touches to your mousemat before bein able to face them? the only problem is its considered by some to be too sensitive...the only thing i can say to them is..get used to it
=)