Looking to buy a computer

I've been looking at this setup for some time now since I've wanted to get into gaming with friends and family and have been looking at things from all different perspectives and would just appreciate some input

Case:
Apevia X-SniperG Mid-Tower

PSU
580W

CPU:
(Sckt775)Intel® Core™ 2 Duo E8400 CPU @ 3.0GHz 1333FSB 6MB L2 Cache 64-bit

Motherboard:
EVGA nForce 750i SLI FTW

RAM:
4GB (2x2GB) Corsair PC6400 DDR2/800

Video Card:
NVIDIA GeForce 9800 GTX+ 1GB 16X PCI Express

The only thing I've noticed is that the mobo has a 8-pin connector and if the psu only has a 4-pin will that be a problem? I'll buy an adapter if I have to or upgrade it later.

Any suggestions are welcome, Thanks

The PSU is one my friend is giving me, since he bought a bigger one since he is running SLI. Not sure on the brand name though

I've already got a 22'' LCD and I'll be getting a 500GB Seagate Hard drive with Windows XP 64 bit but I would like to stay under $1000 but I would consider the benefit if it spills over a bit

I'm looking to play some FPS, COD4, UT3, Most of the games in Orange Box, I like to get a little Combat Arms mix in there

And yes I am building this myself
I have put together previous PC's and have helped friends build theirs so I feel comfortable with them

The only thing I haven't done is overclocked and I probably won't be doing this myself unless I can be sure that I wont fry or damage anything (TBH I'd freak if something like that happened)

A few suggestions:

• Make sure that your power supply will be sufficient. If you're unsure, take a look at the big label on the side, and tell us the brand, total wattage, as well as list all the +12v rails, and tell us how many amps each is rated for.
• The resolution that you'll be playing your games at, and of course what games, will heavily affect what sort of video card you'll need; the highest-end and most expensive graphics setups (such as those with 2, 3, or even 4 GPUs total) are only necessary for those that play at stupidly high resolutions, POSSIBLY as low as 1920x1200, but really going upwards to, say, 2560x1600. Most gamers play at more "normal" resolutions ranging from 1024x768 to 1680x1050.
• For gaming, I'd personally take your currently-selected Core2Duo over a Phenom II. Phenom IIs are a good choice if you want an inexpensive quad-core CPU, but quad-cores are NOT gaming CPUs, as games only even make partial use of the second core; the E8400 is a very solid choice, since even though it has only 2 cores, each of those cores is more powerful than any individual core you'll find on ANY CPU AMD makes, and more powerful than the cores in most quad-core CPUs Intel makes, plus it's cheaper than pretty much any quad-core. Result: probably the best bang-for-your-buck out there for gaming.