GREAT world textbook!
Has anyone else used The Earth and Its Peoples, a Global History (3rd Edition, AP Edition) by Bulliet, etc? It might not be the best for sheer detail, but it explains cultural interactions wonderfully. I've also read Spielvogel and Duiker's World History, and The Earth and Its Peoples is definitely the way to go for AP World History preparation. It has a ton of maps and explanations that really elucidate what's going on and do so in a way that retention is inevitable. Just my opinion.