global load balancing strategies for high traffic sites

Hey everyone, I've been pondering how to handle scaling for a while now. For sites with users all over the world, what are your best methods for global load balancing? Sure, basic geo-DNS is a start, but what more sophisticated approaches are you using to keep latency down and make sure the site stays up for people everywhere, no matter where they are? I'm really interested in hearing what works for you and what tools you like.