I use a Logitech M905 and it's great. Nice size, batteries last for ages, the nano receiver fits inside the mouse when you're carrying it around. The nano receiver also means I can fit it in next to my extra wide 3g aircard. Fits nicely in the hand and comes with a little carry bag. Buttons all configurable with the Logitech software. Took a little getting used to after using a hi-res Logitech G5 gaming mouse for years but no complaints.
