After my two sons and wife finished #4 (Goblet of Fire), I decided perhaps I should read these books to see what all the fuss is about. Since my wife read them, I wasn't too worried about some of the criticisms I was reading about them, but I figured I should read the first one or two so I would better be able to put the books in context for the boys (it's a dad thing, I know). I read the first 3 books in 3 days and did the fourth over the following week. They are a fun read and I was hooked.
If one can have a literary patronus, then I guess mine would be G.K.Chesterton.