Hey, you've read John Scalzi and you've read the Xanth series. Admittedly, Xanth is a BIT ****ty, but hey, it works.
I can't help you. Personally, I really like Discworld, for something specific, and for something general-- a lot of Baen (it's a publisher) science fiction is a LOT of fun-- entertaining, funny, and all that. Might start slow, but it ends up awesome (I'm partial to 1632, by Eric Flint, it was the first thing I read from them.)
But honestly, just find something you enjoy. I can't tell you what you'll like, but lighthearted humor usually works to one degree or another.