Looks like u arent on a budget, Heres a list:-
MX510 (28USD + Shpping on Newegg)
5.8MP, 800DPI
Pros:-
------
8 buttons
ergonomic
cons:-
------
right handers only
============================================
MX518 ( 49USD + shipping on Newegg)
1600DPI, 5.8 MP
Pros:-
------
8 buttons
On the Fly sens adjustments
Ergonomic
Cons:-
------
Right Handers only
==========================================
Razer Diamondback(53USD + shipping on Newegg)
1600DPI, 5.8MP
Pros:-
-----
7 Buttons
compact
On the fly sens adjustment options
LAN pouch for carrying it around
COns:-
-------
Small, wont fit into a big hand/palm
=============================================
If you are right handed and want the OTF sens adjustment feature, go for 518. If you want a compact mouse or if u are left handed go for db. I dont think u get IE3 anymore, but ie4 is not good for gaming IMO as it doest have a clicking scroll wheel and you might want to use mousewheelup/mousewheeldown binds. Go, for mx510 if you arent particular abt the OTF sens thingie and have a big hand(and u shud be right handed of course
). I think u might want to consider the Microsoft Intellimouse optical 1.1a(5 buttons), IIRC its the same sensor as the Intellimouse explorer series but comes in an ambidextrous chassis( Either handed ppl can use them, unlike IE3 being right handed only) and is a bit less bulkier than the IE3/4.