Well, I'm finally getting a new pc, and I have an $800 budget.
Www.newegg.com has an amd dual core 4200+ for $187, so I think I have the processor down.. So now I need some advice on everything else

I have a friend building this for me, and he was just going to put what he thought was the best for my budget, but I'd like some more input! I already have a monitor, keyboard and mouse. So I only need to build a tower. I really don't know anything about vid cards, how much ram to get, what kind of MoBo, and so on.. So if someone could help me out, that would be awesome!
Thanks