Gorgon Heap: IMO, Dune Messiah sucks canal water, but Children of Dune is pretty good. Have not read any other Dune books.
I can also recommend some of Herbert’s other stuff. The Santaroga Barrier, Whipping Star, and Under Pressure are all pretty good novels.
Don’t forget “Dosidai” or whatever it is called - the sequel to “Whipping Star” with the BuSab - we need such a bureu in our govt sometimes:)
The Dosadi Experiment.
Oddly, I still have not been to a book store. They are just too far away.
Well, someday.
well, once I finish this email I’m gonna trot down to the bookstore on the 2nd floor and at least pick up God Emperor. . . People have constantly told me how boring the later series gets, but if “boring” means “heavy on internal dialogue and philosophical/religious/political insight” then I’ll likely be unable to put the damned things down.
I also had the chance to read a lot of his other novels, and was particularly intrigued by “The Godmakers”, which is like the “Dune” Beta. . . You can see so many elements from his inidividual novels that made their way into the Dune series.
Off I go!
Definitely do MLC, you would enjoy the later books.
Herbert fans fall into two camps, either the series gets stronger as it progresses, or it gets weaker.
What is agreed upon is that the series steadily becomes less focused on action and suspense, and more heavily involved with politics, internal struggle, philosophy, etc.
I much prefer the later books, God Emperor being the finest by far of the series (IMO of course). Heretics and Chapterhouse are tied for second.
Book 1, in isolation, reads to me like action space opera. It is only with the full breadth of vision of the later books that Book 1 really starts to shine and take on life.
I have God Emperor in hand now, and am counting seconds 'till I can get away with reading it (I’m at that miserable thing they call “work”).
When I was a teenager I loved the action/suspense. The last time I read Dune, however, it was like I’d been hit by a 2x4. The philosophy, etc just sucked me in, and I chewed through Messiah (a disappointment - it has little of either action or philosophy) and got to the creamy filling of Children. Then I ran out of books! 
That’s something that I’ve remedied.