For your RAM, I would get 2X512MB, which totals 1GB. Getting 2 sticks, will let you run them in dual channel mode. Dual Channel doesnt increase performance too much, but you might as well utilize it.
If you feel rich, then sure, get 2GB (2x1GB). You wont really notice much of a difference between 1GB and 2GB, though.
Patriot is a good brand. Most readily available brands of RAM arent really of poor quality. The thing that really sets RAM apart (unless you are overclocking) is the warrenty. If you DONT get RAM with a lifetime warrenty, then get another kind.
Venice and San Diego are both cores of CPUs. San Diego is basically the same thing as Venice, but San Diegos have more cache (actually 2x L2 cache).
As for newegg, they seem to have pretty good prices for the most part, but I have heard people suggest www.zipzoomfly.com
here as well.