New Build, will it be enough?

[iLL]

My current PC I am bored with, lol sounds weird huh?

Current Spec:
Intel P4 3.0ghz
Abit AG8 Mobo
2GB Corsair memory
80GB Maxtor SATA
250GB Maxtor IDE
CD/DVD Burner
Floppy
500 Watt Antec Power Supply
Soundblaster X-Fi
BFG 7900GT
Coolermaster Case

I already Pre-ordered Vista so I am planning on building a new comp just for Vista, but would like some opinion(s) on my choices in hardware. I have chosen...

Case: Antec Nine Hundred http://www.newegg.com/Product/Product.asp?Item=N82E16811129021
Processor: Intel Core 2 Duo http://www.newegg.com/product/product.asp?item=N82E16819115003
Mobo: Abit AW9D-MAX http://www.newegg.com/product/product.asp?item=N82E16813127011
Memory: Corsair XMS2 http://www.newegg.com/product/product.asp?item=N82E16820145034
Hard Drive: Western Digital 250GB SATA http://www.newegg.com/Product/Product.asp?item=N82E16822144701

I plan on using the floppy drive, cd/dvd drive, and the x-fi in the new setup. Now here is where I am having the most trouble deciding on things. Should I keep my current BFG 7900GT(PCIe) and buy another to use SLi or buy a 8800GTS or 8800GTX. Also I'm not sure what power supply I will need to run all this. So if someone could recommend a power supply that would be great.

[RamonGTP]

I would rather have a single 8800 than 7900's in SLI

[MadPistol]

I have the same case, processor, and memory as you have listed

Also, if you want SLI, you will have to go with the nforce 680i chipset. The current chipset you have listed is crossfire only.

Definately get an 8800 GTX over 7900 GT SLI's. No doubt.