My only advice on the Dune series is: read the entire series, all six books, cover to cover, in sequence, before you decide how you feel about them. There is a big story behind all the details.
So why is this worth reading, and what does it all mean? Well, if you've read the series, you might want to read a Usenet posting that I wrote a few years back. I'd welcome any further conversation on this topic, if you care to write.
I also recommend the three prequels by Brian Herbert and Kevin J. Anderson:
They have access to Frank Herbert's notes and unpublished materials (Brian is Frank's son), and I think they've done very credibly with it. The plotting is suitably Byzantine, and they definitely held my interest despite knowing a lot about who lives and who dies. They're working on an even earlier prequel covering the Butlerian Jihad, and I will definitely be looking for it.