Mostly loving the Arc Mouse (http://www.amazon.com/Microsoft-Arc-...rc+touch+mouse).

My only complaint with it is that it doesn't have the back button you use with your thumb. I love that it goes completely flat for traveling - I can easily stick it in a small pocket of my messenger bag, and the USB receiver sit snuggly on the back of the mouse when flat. It uses a surprisingly strong magnet to hold it in place.