The 1984 movie was my introduction to the Duniverse as well. I remember going and getting the book immediately and loving it. It's easily my favorite book and I don't think anything will ever top it. I loved the miniseries as well, despite the budget limitations. Ian McNeice as the Baron is just spot on. They should ask him back if they ever get another movie made.
^Yeah, McNeice gave the Baron the cunning intellect that was very much present in the book but rather lacking in Lynch's film. Not that actor's fault of course, as the flamboyant, deranged, pustule covered version of the Baron fit very well into the context of the film...which says a lot about how far removed the film was from the book in certain areas.
That aside though, I'm rather fond of some of the other casting in Lynch's version. Off the top of my head I think the actors that played Piter, Thufir, Stilgar, Jessica, Yueh (I want to put Irulan in there too, but she was barley in the film) were all very well cast and by-and-large, "better" than those that played those same parts in the 2000 mini series (not so much in CoD as Krige and Berkoff were much better as Jessica and Stilgar.) I'm sure there are others that are good or bad, but those are the ones that stand out for me.
When it comes to Paul, the weird thing is that while I prefer Kyle MacLachlan as the young Paul (even if he was really too old for the part), I rather like Alec Newman's take on Muad'Dib and where I think he most especially shines: The Preacher.
As for Gurney, I don't think either P. H. Moriarty or Patrick Stewart did him much justice, so I'm still waiting for someone to nail that character.