The standard wireless mouse can only free you from cords, while your arm will remain latched to the desktop almost defeating its purpose. The Perific Dual Mouse frees you of both cords and the necessity of a desktop for mouse control. Outfitted with an optical trackball and an ergonomic design, the Perfic mouse allows computer control from up to 6 feet away. Even hold the mouse in hand as you type allowing for fast switching between each input device, or just use it as a normal desktop mouse. Available here for $120.
Product page here.