Like some of the others have said here, a gaming mouse is really a personal preference. Overall I'd have to say the G5 is probably going to appeal to most gamers but it depends on what you're used to.
I had one of the original razer gaming ball mice (boomslang) and I loved it. Good "click", the scroll also clicked (great when you have scroll set for weapon list, you don't pass the weapon you want), loved the two side buttons (two large ones on either side, not two tiny ones on one side), and big teflon feet.
I'm a logitech fan as well, I have:
G15, MX1000, G7, Razer boomslang (still working) and Razer copperhead and the various crappy MS and Logitech mice (probably 5-6 around the house somewhere).
I also have the Xactmat from razer (gaming mouse pad).
I currently use my copperhead for all FPS games.