I saw a miniseries version on Canada's Space: The Imagination Station, long before it was bought out by Corus. It was an early-aughts-era made-for-TV miniseries, but I thought it was fantastic.
This must be the John Harrison "Frank Herbert's Dune" miniseries made in 2000, followed by a "Children of Dune" miniseries in 2003. My wife and I are watching these right now -- no special coincidence, we're just working through our DVD collection in alphabetical order and it was next on the list.
The miniseries is indeed good. Harrison makes an admirable effort to closely follow the story, Ian McNeice pulls off a suitably creepy Baron Harkonnen and the special effects (although outdated by today's standards) are quite good for the time.
If you're a Patrick Stewart fan like we are, you can go back to the great 1970's BBC miniseries of the "I Claudius" novels and see a much younger Picard sporting curly golden locks as the Sejanus character.