Favorite SF Series: List of 10

Lists are fun.  Some lists can really stir fans’ passions about their particular topic.  I always enjoy reading “Best” or “Most influential” lists of Speculative Fiction books.  The comments found with those lists are often great ways to find new books.  With this in mind, I’ve decided to write up my list of top 10 favorite SF series.  I’m not saying they are the most influential (though some certainly were) or the “best” (except to me), but I’m eager to see what you all have to say.  Would any of these end up on your favorites list?

These are not in any particular order.  Narrowing down to 10 was difficult enough.

1. Lord of the Rings by J.R.R. Tolkien.  It is ubiquitous, but I’m a fan.  My first SF reading when I was a child, and here we sit at the 60th anniversary today.  Time for another re-read, I think.
2. Of Memory, Sorrow, and Thorn by Tad Williams. My second large series read, and full of the complex, world building that the author is known for.  The series is currently out from HCPL, but will be returning to our collection soon.  Bonus: Tad Williams is revisiting the world in the next few years.
3. Dresden Files by Jim Butcher.  I’ll admit, I’ve skipped books 4-8, but these stories are fun, quick, and reliably great reads.
4. Stormlight Archive by Brandon Sanderson.  This is a new series, with only two books out, but it is already a favorite.  Huge, wonderfully complex story with true characters and rich imaginative world.
5. Mistborn by Brandon Sanderson.  Double dose of Sanderson on this list, but I’d list all his stand-alone novels, too. 
6. Dying Earth series by Jack Vance.  This book has the series in one volume, and while it comes under four titles, they are in themselves collections of short stories and novellas that are narratively linked.  
7. The Chronicles of Amber by Roger Zelazny.   I've only read through the first cycle (The Corwin cycle), but just those alone make this one of my favorite series.  Not unlike Philip Jose Farmer's World of Tiers, it has a large family dealing in a multi-universe with intrigue and political upheaval.
8. Foundation by Isaac Asimov.  Another of the ubiquitous ones, just more to the tech side of the genre.  This series, and more specifically the initial trilogy, are SF standards.  The trilogy was the Hugo award winner for  "Best All Time Series" in 1966.
9. Hitchhiker’s Guide to the Galaxy by Douglas Adams.  Witty, silly, and profound, an interesting mix to be sure; just remember your towel.
10. Earthsea Cycle by Ursula K. Le Guin.  Another of those that is deft in its world building and has the art of adventure and depth of character to become a favorite among many readers.