Not completely secular, but I've enjoyed Story of the World. It isn't perfect, but it's easy (and as I think I've said here before, sometimes "easy" is perfect!)
We're about to finish up the fourth volume, and from here on out my plan is to do topical history rather than a curriculum.
We've also dabbled in The History of US (U.S. history -- more detail than I wanted right now, but filled in some gaps in SOTW) and History Pockets by Evan Moor (definitely crafty, but not half bad for specific topics).
