I steer clear of mini mice. They hurt my hand after 10 minutes.
I want a wireless mouse the same size as a normal desktop mouse. I don't need 30 buttons, and I don't want to pay over £30

And I really, really don't want a USB receiver that's bigger than those nano versions. Why in the name of sanity do they still bother to manufacture the versions that stick out the back of your laptop by 2 inches?
EDIT: why is it useful for the mouse to be physically smaller? It doesn't save significant space or weight, it just gives users cramp. A normal sized mouse will still balance on a small flat surface and be very usable.