Build a high end gaming system for around $2000

I want to build an ultimate gaming system that should be able to handle anything with heavy emphasis on stunning visuals and system speed. Let me hear about your best MOBO’s, CPU’s, crossfire or SLI video cards. power supply and which type of drives to utilize. I haven’t set a price as to how much I would like to spend yet, but 4gb video cards at $2k are a little out of my price range. I am looking for a system that will stand the test of time or at least a couple years before needing anything to upgrade.