Best mouse that work with iMac internal bluetooth?

I have the wireless mighty mouse for my new imac. However, I realized that it is not ergonomic at all. My hand don't feel comfortable with it. I tried using my old Longitech MX610, but iMac internal bluetooth can't detect it, I know I can plug in the USB bluetooth and make it work, but I just wonder is there any good mouse out there that can work like the wireless mighty mouse without plugging any USB wireless bluetooth. iMac only has 3 USB ports, I don't want to use it on this.

RadTech's bluetooth mice should work out nicely for ya. One nice feature they have is that they charge by a mini USB cable rather than a dock. So if you have one of those types of cables around to charge a cell phone or headset, then that's a bit less cable clutter to add to your desk.