Well I like Heretics and Chapterhosue better than God Emperor...
The Legend trilogy is interesting, however it's a bit too fanficish
Let's see how EVERYTHING we've seen in Dune started ten thousand years ago!!
House trilogy is almost on par with the first 3 dune books. Must read.
Paul of Dune is similar to the House trilogy in style, in substance it's a little weaker.
Haven't read Winds, I should really have bought it by now...
The two sequels are extremely interesting, the characters are drawn perfectly, however there are like twelve threads going on, third of them completely separate from the main story, some even pointless. And it takes 5 deus ex machines (hehe, bad pun) to save the day!
If you got time, go ahead!
You can read it in any order, just read the House trilogy before Paul, and the Legend trilogy before the sequals. And after you finished with the House trilogy, reread Dune. It makes it MORE AWESOME!