I recommend you get what you want.
People can fight and debate on computer hardware untill they are blue in the face when it comes down to it do your own research and get what you think would do/cover what you need/want it to do.
My "Suggestion" is to go with at least 2 gigs of ddr2 running at least 667mhz try to break it down into as small sticks as possible if you have 4 dram slots get 4 512's if you have 2 slots get 2 1gig etc the reason is the more slots you cover the faster the information can get in and out.
Graphics, well lol there is so damn many chipsets its unreal so stick with one that wil do what you need it to do like if you want to play the latest games on all highest settings go with "ati-x300-x700-128~256mb mem" or "nvidia-fx6400-fx6600-128~256mb mem" if you want to run the games with all possible options on and even future games get the highest end cards "ati x800-x1800-256~512mb mem" or "nvidia-fx6800-7800-256~512mb mem" as I said it just depends on what you want it to do.
"I" am using the ati x850xtpe 256mb I have yet to find anything that can bog it down.
A note on the fx7800^ the 24 texel pipes are really 16 hardware and 8 software.
