MS Intellimouse Explorer is hard to beat. Save a bundle buying the OEM version and download the driver from Microsoft.[I bought another recently on special offer for £19 and PCWorld online want £39.99 for the retail box!]
I got a nice optical wireless rechargable mouse from Ebay. It was a new European import which needed an 'electric razor' adaptor but the chap I bought it from included that and a set of rechargable batteries. I paid £15 + postage but I know others have paid less. Might be worth a look.
It is silver and has its own docking station. I would guess you get about 10 hours of use from it before it needs recharged again. About once a month for me.
Because there can be some lagtime with wireless mice, and if your're playing an online fps that gets you shot, though have to say they are a lot better these days.
The Mystify Razer Boomslang 2100 is the ultimate USB gaming mouse, faster and more accurate than any mouse that has gone before it! This is due to its maximum resolution of 2100dpi, the highest ever achieved in a USB mouse. The extreme accuracy supports gamers as well as all other PC Users. The ultimate gaming mouse features pixel exact targeting in games, relaxed gaming and office use because of less mouse movement and user friendly adjustment with the provided software. This was copied from