Upgrading gaming system

Hi, I'm looking to upgrade my current gaming PC, I'm currently using a Core2duo e6300, Asus P5b motherboard, Nvidia 8800GTX, 2x2gig DDR kingston ram, 300gig HD (random WD thing), 520watt cooler master real power PSU, 22" LG Flatron (1680x1050 res) and a few other bits and bobs. I got a little less then $1000 to spend (700euros)

APPROXIMATE PURCHASE DATE: A.S.A.P.

BUDGET RANGE: $1000/700euros

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Used mostly for gaming, watching some movies.

PARTS NOT REQUIRED: Don't need a keyboard, mouse, speakers, monitor(i think)

PREFERRED WEBSITE(S) FOR PARTS: Since I'm Dutch, I normally go to http://www.perfect-systems.nl, but since its got quite a wide selection, I dont mind getting advice from stuff on Newegg.com or anything else.

PARTS PREFERENCES: Only thing I'm quite certain of is really an Antec 900-2 gaming case.

OVERCLOCKING: No

SLI OR CROSSFIRE: Maybe

MONITOR RESOLUTION: 1680x1050

ADDITIONAL COMMENTS: -

I'm just quite a noob to upgrading a PC or just getting parts in general so I would really like some advice on how to boost my system the best with the available budget. I've looked around quite alot but im having alot of difficulty deciding how to boost my performance the most. So some advice would be much appreciated

I don't mind stepping over to AMD at all, I'm just having a hard time figuring out what to replace everything (or just some parts) with to get the maximum performance allowed with my budget.

My current motherboard does not support SLI afaik. One of the main things I'm looking at for upgrading is my processor and get a bigger and faster hard disk, but with the budget I got I should indeed be able to crank a few more pieces up abit. It's just really hard for me to make a choice out of all the available options, even having looked through all the charts and reviews for most of my options, I'm struggling to find the most suited combination to get within my budget.

Would a be worth spending a little bit more money and getting an Intel i920? And if so, what would the best motherboard/memory be for using that?

What I'm looking at getting atm is the following:

Case: Antec Nine hundred (or maybe Nine hundred-two)
http://www.newegg.com/Product/Prod [...] 6811129021

PSU: Corsair 650 TX
http://www.newegg.com/Product/Prod [...] sair%20650

Graphics Card: Asus ENGTX275 896mb
http://www.newegg.com/Product/Prod [...] k=enGTX275

Hard disk: Simple WD 640gig HD

"get an i7 CPU, X58 mobo and 4GB of ram, that should be about 500-600 euro's, then with the spare cash, get a PCP&C 750w PSU and a second 8800GTX.

all of that comes to 655 euro's on OCUK but the 8800GTX is 'B grade'. "

Just so you don't confuse him and you aren't confused yourself, he can't get 4Gb of RAM with an X58 setup. The boards are tri channel so you'd have to get either 3Gb or 6Gb.

^ sorry, was a bit sleepy at the time, I meant 6GB.

a P6T is generally the best option, it's cheap, has CF and SLI support, and most of the time you don't need the features of the more expensive boards.

As far as building, there are guides all over the internet to help. To me, the hardest part was getting all the wiring for the case connected properly on the mobo, but the mobo will come with a guide.

For the PSU, I'd get the Corsair 750 instead of the 650, just to be safe for if you do SLI. Don't have any idea on the case fans in that case, but Antec usually builds nice cases.