I used to be a strict Intel/Nvidia motherboard/graphics card person, but after 10 years I bought the 9800x2 and was getting 15fps even 6 month after I bought it, and massive stability issues. I switched to ATI reluctantly and bought their equivalent and never looked back.
I now run a ati 5970x2 and whilst it's pretty quick, the problem is I have ongoing problems with cursor corruption even after a complete reinstall of Windows. I am told it's a common problem with these dual gpu cards and I should look at the nvidia top end single gpu cards or perhaps even the new ati single gpu top end cards.
What's peoples opinions on nvidia/ati these days?