Would having an ATI radeon video card effect my PC or do anything if I have a built in Nvida chipset?

Alright so right now I have an Nvidia build in video card in my motherboard ,and I am running an ATI radeon card, I'm going to upgrade thursday. Would it be better to get a Nvidia card , or would it make no difference at all?|||It won't make a difference|||Nope you are good to go. You may have to change the video source in the bios but that's about it.