If you use an external keyboard (which I recommend whenever portability requirements don't prevent it) and want a "real mouse," on some older laptops the external keyboard and external mouse use the same port, even if there are separate connectors. I don't know whether that's still the case for newer ones. If you find that to be true, you may want to substitute a USB mouse.

The "nuisance" touch pad, that sends your cursor to a random place in the document any time you touch the pad while typing, can usually be turned off, but plugging in either an external "standard serial" mouse or external keyboard sometimes forces it to turn back on. (You add a mouse because you want to get rid of the touchpad but the serial mouse doesn't work unless the touchpad is turned on.) If yours works that way, adding a "standard" mouse may force you to use an external keyboard as well (unless you're willing to learn to type with your thumbs pointing at your nose to keep the thumbs off the touch pad while typing). You should be able to add a USB mouse with the touchpad turned off.

John