Built it yourself, custom internet builders usually charge you anywhere from $100 and up just to put it together, quite a rip-off, as long as you know what you're doing.
Do you have any experience building PCs? What are you using right now?
Also, the Nvidia 8 series are going to be very expensive when they first come out.
But the good news is they are going to push the prices down of the 7 series quite a bit.
If you can wait a few months for the prices to come down, do that.
For example, I'm going to build a new PC in March, and I want to use a DX10 enabled card later this year, so I'm going to buy something like this http://www.newegg.com/Product/Produc...82E16814102691
to hold me over until they come out.
Is it the greatest card? Not a chance. Will it do me well enough until DX10 cards come out and save me money so I have more to buy a sick DX10 card? Absolutely.
(or something like a refurb 6600gt pci x16 or refurb 6800, you get the idea).