I use a windows machine for gaming FPS. To this end, I just bought a new mouse that has amazed me. This is a Mad Catz RAT 3 wired mouse..
The version 5 or 7 may be better, but the RAT 3 is what I could afford. I am still amazed! I have never used a faster mouse, or a more comfortable mouse. This thing is incredible. Wish I had bought one back when they came out.
If you play fast moving FPS in Windows, check out this mouse! It also works with Macs.