What kind of mouse do you like for gaming?

So I personally chose the Logitech G100s mouse for my gaming setup. It's just a regular old mouse with a wheel and a left and right button. The only addition to it's otherwise normal appearance is a sensitivity button that cycles through low, medium, and high mouse acceleration.

Basically what I'm wondering is what kind of mouse do you personally prefer. I see lots of my friends and people online who use Razer Nagas and other mice with tons of buttons but I don't like those. I prefer the 2 button setup and yes I do play genres like MMORPG's and MOBA games and it's doesn't hinder my playstyle at all. In fact I'm usually better than the friends who use said mouse. In the end though I'd just like to know what your personal preference is and why?