I loved the 1st book, but the 2nd and 3rd were terrible, and I didn't continue after giving up on the 3rd.
Not sure why they are "SF Classics."
 
 This is precisely the reason. Anyone I've asked has given mixed reviews. Oh, and being completely worm/snake phobic hasn't helped.
 This is precisely the reason. Anyone I've asked has given mixed reviews. Oh, and being completely worm/snake phobic hasn't helped.   
However, I loved the series. The only one I had a hard time with was God Emperor of Dune. I liked the complete flip-flop of society in the later Heretics of Dune and Chapterhouse Dune.
I think Dune was a brilliant series, sadly left uncompleted. It not only encompassed The Iliad, but predicted the current Gulf Wars decades ahead of time.
quote:
Not sure why they are "SF Classics."
To answer your question:
Elements of Dune can be found in much of Sci-Fi, from Steve Perry's Matador series to Star Wars. Also, it is like the Lord of the Rings of Sci-fi -- with the exception that each component of the story is a stand-alone novel. 
 
But it is a classic, it's had a significant influence on the SF genre, and my opinion of it doesn't change that at all.
 
Fair's fair, though...I've read only a smattering of the recent stuff, a lot of which is probably just as good as the "classics" I remember.
(For lack of a better place, I'll mention I just picked up another reprint, a new collection by the late Poul Anderson: To Outlive Eternity and Other Stories.  Some great stuff in there.  I'm still impressed by Anderson's work---but I was quite shocked to realize it's been at least twenty-five years, maybe longer, since I last read "No Truce With Kings," collected within.  The collection seems to be easily available...if you're curious, pick it up.)
 
Anyway, I loved it. And I'm in the younger generation. I loved how complex it was, a "meat" story and not just glamorous fluff. Seems to me there's not too many of those these days...
I did see the influence it had on Star Wars, definately. 
 
Dune - Loved it
Dune, 
Messiah - Least favorite but still enjoyed it
Children of Dune - Nice twists and has a flavor similar to the first book
God Emperor or Dune - Radical departure in tone, this is where alot of people stop reading them, it is a good book but aside from setting bears little resemblence to the earlier books.
Heretics of Dune - Continues the tone of God Emperor and is enjoyable if you can make the shift
Chapterhouse Dune - This is often belittled as nothing but two nuns arguing for 600 pages, I did not find the book to be like that at all, I thought the dialogue they had was well interspersed with the Bashar storyline and it even kind of ended with a classic cliffhanger.
The prequel books are worth reading just to glimpse the source material that Frank Herbert was working from as executed by his son and Anderson.
The pre-prequels set during the original Jihad were not so interesting, but still worth a look if you are a true Dunehard fan.