I haven't reread the books since I was a teen. But in my memory, and my experience of them at age 11, they were way better. I think that the show took some of the FEEL of the characters, as they are HINTED at in the first four books (and much of real character development doesn't really happen until the end) and went from there. It's like they took the end point of the books as a starting point for the series and went from there.

If you REALLY want some CRAZY ASS LULZ, read The Return series. They are some of the WORST books I've ever read.