Why go wireless? I DON'T want slower response speed for a mouse that costs a fortune, I DON'T want lag when the mouse is idle to save battery life, and I DON'T want to mess up with having to either recharge batteries that never last (I have enough batteries to take care of) or get stuck in the middle of a Sunday because the batteries expired and I have no replacement pack.
In short, forget Bluetooth or wireless mice - they suck.
To me, the best available mice are the Logitech mx510 and the Microsoft Explorer with Tilt wheel. I don't know which one to buy, but I think the Tilt wheel is a little overkill if you don't use Excel a whole lot, and I don't like the fact that Microsoft's vertical wheel has no increments anymore, and that's a little unpleasant.
I guess nothing beats my IntelliMouse Explorer 1.0