I find optical is way better for gaming. Just look at halo for the pc. I tried trackball and it just seems a little less comfortable and the reaction time is way better on optical. I used to play halo on the pc tournys all the time i tried my friends track ball and i just got thumped into the ground when i did. I have the logitech elite duo series. Its a really awesome set. I myself don't go for all that extra features to be honest tho. Most of it you will never really use. But some of it is nice. To many buttons on a cordless mouse tho really kills the batterys qcuikly. Even rechargables can be a pain.

I've never seen a serial optical mouse. As far as I can think of, the serial port doesnt supply any kind of power. Therefore you have to go usb. If your concerned about using up all your usb ports, buy a PCMCIA USB 2.0 4 PORT CARDBUS HUB ADAPTER. That will add an extra 4 usb ports to your laptop. The only drawback is that if your laptop has only one PCMCIA slot instead of 2, and you rely on that for wireless internet, then you have to sacrafice one or the other. Click the link below to see what a PCMCIA Card is if you dont already know.

Depending on the usage, mice, even the generic ones, can last from many months to a couple of years. By then, you'd probably replace them with a newer, sleeker model even before their life starts to ebb since mice are relatively inexpensive. You could buy a really cheap one as en emergency backup if you are still unsure.