Seems like a good deal. If you are happy with the speed. Extra memory always helps, but you may find you pay as much for it as the laptop itself.
A reinstall will get rid of all the clutter that has probably built up. Just make sure you backup anything you want (particularly any drivers to save you digging around later) Also any download any microshaft updates and install them before connecting to the internet.
I would personally go for 2000.