I like the logitech V450 NANO ....
I buy 2-3 of them a year (I have 5 workstations in my office) .... I am extremely hard on mice, and these ones stand up better than others .... battery life is amazing, and being a laptop mouse, it is smaller and more comfortable to use for long periods of time!! The nano receiver that is smaller than a bluetooth dongle is a great selling point too!
