Definitely read Dune. If you like it enough, go ahead and read Dune Messiah; it’s not as good as its predecessor, but still serves as a solid coda.
As for the remaining books … I can’t say whether or not they’re worth reading, but Children & God Emperor of Dune weren’t my personal cup of tea. I found Children rather meh, and I got roughly halfway through God Emperor before the cynicism exhausted me.