Here is the problem. Tonight I decided to call AppleCare figuring I could get a good answer. When the guy answered I told him I am getting a Mac Pro and asked my question. Before I knew it he was explaining how the "MacBook Pro has two video cards in it already, one for the internal LCD, one for an external" I explained I have a Mac Pro coming, not a MacBook Pro. I hope I'm not wrong but I almost explained to him that the MacBook Pro only has one video card.
Then I explained it was the Mac Pro and how I want to know if I could use an NVidia G8800GT with an ATI 2600 XT and that I would be using it with 3 monitors. He said to hold on a minute and he would check into it. He came back in minutes and said he talked to several other csr's there that specialize in desktops and they told him that you can't use an ATI with a NVidia, you can only use one card type.
The next part is what shocked me, he then said how before I buy another video card to check with the manufacturer to make sure it works with a Mac Pro. I explained I'm not buying a graphics card from another manufacturer, I'm buying Apple's graphics card. Well he tried to tell me Apple DOES NOT sell video cards. I realized at this point I was not going to get any help. I never have had problems with calling Apple in the past but am shocked he talked to others who gave him this information. I also realize now that I should not take his comment seriously about them not working together. What I'm wondering, does anyone know yet if these two will work well together?