The mouse I currently use is the Logitech M705.

Of all the Logitech mice I've used, its by far the most comfortable mouse and has multiple customizable buttons.

I'd say its rather affordable and has a battery life of up to 3 years which is pretty insane.

Here's the Amazon link: http://www.amazon.com/Logitech-Wirel.../dp/B0034XRDUA