I actually haven't read all THAT much Chesterton. My Dad and my brother are the big fans in the family. I enjoyed his Father Brown mysteries and I've read some of his essays (usually ones Dad gave me in photocopy format...), but a lot of his books are a bit more intellectual than I'd usually bother with. One of these days I'll finish Manalive, and I want to read Orthodoxy...but I'm not really an expert.
I read a Chesterton book last year "The Man Who Knew Too Much". It was very interesting, but I haven't read any more of his writing. I'll check the library to see what they have.
Fr. Brown was mysteries written for kids, right? I think I'd probably enjoy those so I might start there.