I upgraded my laptop from 3GB to 4GB and you can notice a big difference in pep. Much more than I was expecting. Didn't help the graphics quality but helped with the speed at which they get thrown up.
For a home wireless router I recommend Linksys (Cisco). I've tried others and they just can't compete with the stability of the Linksys. I live in a large house with a lot of steel in it and I can get a good signal anywhere.