Fuck the Diamondback. :b I personally use an IntelliMouse Explorer 3.0, and I love it, but I'm not going to only push that on you.
The Logitech MX518 (or 510 if you can find it) is a great mouse and is very solid. A lot of people like the "clickyness" of it, because if you're clicking, you'll feel the click. The shape is also really sharp so if you're into that kinda thang, it's nice.
I love my IME3.0 and it'd be the best mouse in the world to me if it didn't have an issue with some of them randomly scrolling (as in some of them every-so-often "ghost-scroll," which really fuckin' sucks when you use mwheeldown to jump
). It's really comfortable to just lay your hand on.
Really, you don't need more than 800DPI (the IME3.0 is 400DPI, the MX510 is 800DPI, and the MX518 is 1600DPI with the option of lowering that) unless you're playing Minesweeper on a 1" monitor, which is why I recommended the MX510/MX518 over the newer G5/G7. I mean I'm sure the G5 is nice, but it's a waste of money in my eyes when the MX518 is still for sale. If you really want a wireless gaming mouse, then the G7 is the best option I guess.