Motherboard – CPU – video card

I need to build a new computer and was looking for other people’s experience before I make purchases. I do video editing with Avid Liquid Edition and a lot of digital photography, running WIndows on XP. I don’t do a lot a gaming but a solid video card is necessary. My experience in building the past 3 computers was that certain combinations of these 3 items resulted in some components not playing well with the others. I would appreciate some “combinations to avoid” or “great combinations” input from this world of experience. I’d love to lean on some real world experience and not marketing BS.