Need Help Choosing Components for $1500 Gaming Setup

Hello, I build computers as a hobby and I recently received $1500 to put together a dual core gaming system. I am aiming to make around $300 or $400 off this system and I need help on deciding the components.

With Intel's new release of processors and AMD's price drops, I am unsure of which processor to choose. I know Intel's new core 2 duo processors perform significantly better than AMD's x2 liner, but I also heard about the rumor's of AMD's reverse HT and 4x4 quad-core. The person I am building this for would like this computer to be future-proof and I heard that AMD's future chips should fit into the socket AM2, while at the same time have the best performance without overclocking. Could somebody give advise as to which processor would best be suited for these needs? What would be a good motherboard to pair with the processor?

I also need help deciding on a graphics card that will run Counterstrike 1.6, Counterstrike Source, Half Life 2, Day of Defeat source and a few other First person shooters smoothly. I was leaning towards the eVGA 7900GT, but with all the KO and CO versions of the card, I am confused. I also considered at the ATI X1900 and the 7900GTX.

I was wondering if there was a noticeable difference between the OCZ GOLD XTC 2GB (2 x 1gb) ram and the platinum version. Is the platinum version worth the extra money? I've seen the gold for $134 after rebate and the platinum $149.

Could somebody help clear up the confusion and help me make informed decisions on these components? Thanks.

It definitely won't be a selling point, as it doesn't exist.

thanks for the suggestions =D