What is the best road trip to take across the USA from the east coast?

I'm planning on taking a road trip across the USA from the east coast. We've always lived on the east coast so I don't know much about the west coast. I'm wanting to know what routes to take. I would like to stop off at different landmarks and enjoy the best views. Where should I stop off on the way. What should I see? What is the best route to take to see the most?