Been using an MX510 (800dpi) for the last few years. Still going strong.
I use a Microsoft IntelliMouse Explorer 3.0, so it's whatever that comes with.
4000dpi with the Lachesis, i adjust it in game now and then as i play
Revolutionary 800 dpi sensor now captures an incredible 5.8 megapixels every second
G5 @ 800 dpi only