Everyone has a different opinion when it comes to mice. Personally, I love my Logitech G5 so much, that I own 3 of them (one for desktop PC, one for work laptop, and one in my laptop bag for when I travel).

Reasons why I love it:
1) It's corded. I hate wireless.
2) Ergonomic design - fits exactly how my hand should fit on a mouse.
3) Adjustable weight system - lets me adjust how heavy I want my mouse to feel.
4) It's Logitech. I have never had a Logitech product break on me in my life.