I've got a an AMD Athlon 2800+ (2.8Ghz), 1 gig RAM, & a Geforce 6600 GT vid. card.

When I play different games (DoW, C&C3 demo...) I keep getting shades of different colors in the background that flash all over the place... mostly green for some reason.  The game usually starts off fine, but the more I play, the worse it gets.

Is this a video driver problem?  Anyone have a good link to download the updated drivers if it is.  Any other issues my computer may be having?

I'm about ready to build my new PC, I've got $1,600 to spend, I want the best for the $

What I've got: 

19" Samsung 940b monitor (1280x1024 res.), not huge, but VERY pretty

mouse, keyboard, & a lotta love (4 gigs worth)

What I want: 

Something that will take my monitor to the max graphics for RTS games in the next 2-3 years.  Something I may eventually be able to add RAM & video card for SLI to upgrade the performance too.

I was thinking I would like to get an 8800 GTS 320 MB (I've read this is all I need for my resolution, but will highly demanding RTS's such as Supreme Commander cripple the 320 MB?  should I go w/ 640 MB?)

Hoping to get a e6600 core 2 duo proc... not sure if this overkill or not...

Also, I really like the Antec Nine Hundred series gamer case for around $150 unless someone can suggest a better one.

So... not sure about a good motherboard, PSU, quality hard drive & CD/DVD Rom for the $....

So........ for those who care & are willing to help, make me a list!   :D  All tips/advice are appreciate.