Logitech G7
This is the top-of-the-line cordless mouse. I can already hear the fundamentalists yelling "Never!" - that latency and problems with the power supply rule out cordless mice for gamers. Sorry, friends, but you're wrong. The 2.4 GHz transmission guarantees a perfect connection with no dropouts and no latency - ever. USB communication at 500 Hz only goes to prove that.
For the power supply, Logitech supplies two rechargeable batteries in the form of little cartridges. While you're using one, the other is recharging on the USB base station that also hosts the tiny sensor, in the form of a USB key.
And you won't run out of power - an indicator with three green LEDs keeps you informed on the charge level. A fully charged battery will hold up for a week of intensive use. And if you're heading for a LAN party, just bring the charged mouse, the backup battery and the little USB dongle. The mouse's lacquered coating is nice and the design is fairly discreet. Even the weight has been kept within reason for a cordless mouse: 4.4 oz. (124 grams). In fact it's perfect - the mouse is neither too heavy nor too light. Only the $100/110 euros price might make you hesitate. After all, it is a lot of money to shell out for a mouse.
