I had to check the date of the message to make sure it's not from 6 months ago. Man, the fashionable thing these days is HD 4850 Crossfire, not 8800GTS SLI. Check the benchmarks on the Web if you want. Also, SLI motherboards have got a bad rep these days.
If you hate ATI for some reason then of course you have to go with nVidia. Even then, consider a GA-EP43-DS3L and a 9800GX2 rather than a SLI solution. Stick with an Intel-based motherboard, that's the idea. P43 or P45.