I'm a mouse nut. Been through everything from Microsoft's old school optical, logitech dual elite, mx300, 500, 700, 900, 1000, 518, old school razer boomslang, and just got my diamondback plasma LE in the mail.
Verdict:
Microsoft -

Logitech -





Razer -

Logitech's best mice - 5 series and 7 series. The mx700 is an incredible mouse if you get past the weight of it. It is very quick and responsive, just as good as the 500 and 518. 1000 has some tracking issues that I dislike (quick to hibernate, tracks poorly if you tend to lift your mouse a lot while gaming).
Razer - If you can't get a logitech (or are left handed), get the diamondback. Control is on par with the Logitechs. My only quibble with the diamondback is that it's not the most comfortable, and the side buttons need work. Best played with your finger tips, as opposed to resting the palm of your hand on the mouse. My hand/fingers are pretty long and slim, so the diamondback isn't as comfortable as the logitech mice.
Either way, the logitech 500, 518, 700 (if you can get one), and razer diamondback are all exceptional mice.