Hmm. . . well, my list wouldn't look anything like that, because I've only read three of those series. ;)

I'd guess mine would look roughly like this:

1. LOTR

2. Jacqueline Carey's Kushiel's Legacy series

3. Lois McMaster Bujold's Chalion series

4. Ursula Le Guin's Earthsea novels (it's been a looooong time since I read them, or they might be higher)

5. Stephen King's Dark Tower series

6. Barbara Hambly's Sun-Wolf and Starhawk series

7. Lois McMaster Bujold's Sharin Knife tetralogy

8. Charles de Lint's Newford novels

9. Sharon Shinn's Twelve Houses series

10. C.S. Lewis' Chronicles of Narnia

But to tell the truth, I was kind of scraping the bottom of the barrel for my whole second half. . . I just don't read a ton of fantasy series! I prefer stand-alones. . . ;)

Tolkien - Lord of the Rings

Wolfe - Book of the New Sun; Book of the Long Sun

Jack Vance - Tales of the Dying Earth; Lyonesse; Tschai/Planet of Adventure

Steven Erikson - Malazan Book of the Fallen

Edgar Rice Burroughs - Barsoom/John Carter of Mars cycle

Roger Zelazny - Chronicles of Amber

Michael Moorcock - Hawkmoon, Corum, Elric, et al.

Lloyd Alexander - Chronicles of Prydain

I didn't include science fantasy on my list (which is the category I put the Wolfe, Vance, and Zelazny in) -- but I never quite get it when people call the Burroughs series fantasy. Yes, I know there are no actual aliens on Mars. . . but applying strict scientific rigor to genre fiction never really made much sense to me. Is it just because everyone fights with swords? Is it the quest/rescue plotting?

Hmmm...let's see.

1.  Robert Jordan's Wheel of Time.  I'm just a huge fan.  In fact, my husband who is NOT a fan of fantasy/sci fi loves it too

2. Stephen Lawhead's Song of Albion trilogy.  LOVE it.

3.  Stephen Lawhead's Pendragon Cycle

4. Lord of the Rings (and the Hobbit)

5.  Robin Hobb's Farseer Trilogy

6.  Robin Hobb's Tawny Man Trilogy

well shoot.  I'm stumped.  My bookshelf isn't handy so I'll have to check it and then come back and finish.  I've never read Wolfe's Book of the New Sun.  Can you tell me a little about it?

I'm reading a new series right now...the Fires of Heaven series by Russell Kirkpatrick.  I'll have to let you know how it rates...

LOTR

Songs of FIre and Ice

Wrinkle in Time (really YA)

Earthsea

Charles DeLint (there's so much overlap....)

the Celtic/Arthurian books by the woman writer---(having a mindblank!).....

and I'll put a plug in for the new series by Jacqueline Carey---starting with "Nameh's Kiss"

I'm such a sucker for lists like this, even though they cause my TBR pile to grow at an alarming rate.

This list is in somewhat-no-particular-order. I'm short on time and don't want to stall over exact placement.

Lord of the Rings - JRR Tolkein

The King Raven Trilogy - Stephen Lawhead (LOVE IT, LOVE IT, LOVE IT)

Song of Albion Trilogy - Stephen Lawhead

Harry Potter - JK Rowling

The Chronicles of Narnia - CS Lewis

The Dresden Files - Jim Butcher

The Pendragon Cycle - Stephen Lawhead

The Demon Wars Saga - RA Salvatore

The Robin Hobb series has been tempting me from my TPR pile for months now. I really need to hurry up and read it...

I'd have a really hard time listing any series as the "greatest series" that wasn't even finished yet!  Yeah, I liked the Robert Jordan and George R.R. Martin series well enough, but endings matter to me, and count in the quality of the series overall.

Of one's I've read, I'd say:

1. Lord of the Rings - J.R.R. Tolkien

2. Alvin Maker series - Orson Scott Card

3. Incarnations of Immortality - Piers Anthony

4. Harry Potter - J.K. Rowling 

5. Discworld - Terry Pratchett

6. The Dark Tower - Stephen King

7. Chronicles of Narnia - C.S. Lewis

8. Elric of Melnibone - Michael Moorcock

9. Vampire Chronicles - Anne Rice

And if you're counting graphic novels (with books based on the story world in-between), Neil Gaiman's Sandman series would be #10 for me.

"I didn't include science fantasy on my list (which is the category I put the Wolfe, Vance, and Zelazny in) -- but I never quite get it when people call the Burroughs series fantasy. Yes, I know there are no actual aliens on Mars. . . but applying strict scientific rigor to genre fiction never really made much sense to me. Is it just because everyone fights with swords? Is it the quest/rescue plotting?"

I agree, strict scientific rigor has no place in genre fiction as far as I'm concerned.  That's the trouble with a lot of these "Sword & planet" yarns of the sort Burroughs and his imitators spun.  Sure, the setting planet/star system was "real" and perhaps had a protagonist from Earth, but beyond that had more in common with what we now consider fantasy: Sword-using cultures, princesses to rescue, quests, strange alien (i.e. "fantastic") landscapes, and elements like the "9th Barsoomian Ray" that for all intents and purposes is magic disguised as pseudoscience (Clarke's Third Law).  Sadly, the combination of the "Tolkien effect" of the late 70s (that established the "romanticized Western European medieval/renaissance variant with [elves] and [dragons]" as the default Fantasy Setting), the relatively recent trend of microclassification of genres & subgenres, and the deepening Fantasy vs. Science Fiction divide seems to have forced fans of science-fantasy and sword & planet to make all sorts of justification posts on message boards defending our lists...

By the way, Vance's Lyonesse trilogy is straight-up high fantasy, no "science" to be found anywhere. 

But I want to claim sword & planet for science fiction! I'm tired of all these scientists trying to take all the pure fun out of that genre! Fantasy's got its pure-fun subgenre, where's science fiction's? Why can't the future have sword-wielding barbarians awaiting us? ;)

I stand corrected on the Vance. . . haven't read Lyonesse yet, so I didn't know.

SF has some "fun" subgenres in space opera and planetary romance (a close relative to S&P), but I won't stop you from claiming sword & planet for science fiction.  S&P rests equally uncomfortably on either side of the F/SF divide -- great for confusing and upsetting the purists!

In no particular order:

Myth Series - Robert Asprin

Shannara Series - Terry Brooks

Angus Wells - The Books of the Kingdoms

Angus Wells - The Godwars

Harry Turtledove - Videssos Cycle

Robert Silverberg - Majipoor Series

Stephen R Lawhead - Pendragon Cycle

Craig Shaw Gardner - Ebenezum Trilogy

John Morressy - Kedrigern Series

Raymond E Feist - Riftwar Saga

Bernard Cornwell - Warlord Chronicles

The Amber series by Zelazny is definitely in my top 10 list and it's fantasy...but 10 favorite series? I'm not sure I have that many in fantasy beyond LOTR and Song of Ice and Fire, The Dark is Rising, and maybe the Dark Tower depending on how it ends (I'm still reading it).

Memory, Sorrow, and Thorn -Tad Williams: these should be used as bullet catchers to thwart assassins, actually reading them could put a reader into a stupor from which they might never recover

I did find and Erikson ref. - sorry I did not see it......

-wharf rat

The Gentlemen Bastards series is xcellent.

Best fantasy series i've read is the "Death Gate Cycle" by Margaret Weis and Tracy Hickman.  Read it years ago and just now going through it again.  7 books series.

I can't really put these in any real order -- it's like choosing your favorite kid (actually it's probably HARDER than that, let's be honest) -- so here they are alphabetically.

Codex Alera - Jim Butcher

Dresden Files - Jim Butcher

Legend of Drizzt - RA Salvatore

LOTR - JRR Tolkien

Merlin Codex - Robert Holdstock

Mythago Wood Cycle - Robert Holdstock

Thieves' World - Various

I want to get back to reading Song of Ice & Fire.  I want to be up to speed when it hits HBO.  I enjoyed the first book, but I don't think my mind was in the right place and I lost interest in reading a series of massive books.  Hopefully I won't have the same problem when I give the books another go.

I loved series like Raymond E Feist's Riftwar, and Piers Anthony's Incarnations of Immortality books when I was a teen, but it's been so long that I don't know if they would hold up to my current tastes.

These are some of my favorites but I admit I read some of these 20-30 years ago. And maybe some of these are more SiFi.

In no paticular order.

LOTR

Shannara Series - Terry Brooks

Song of Fire and Ice series.

Saga of Pliocene Exile by Julian May

The Belgarid and Mallorean series by David Eddings

Thats what I can think of at the moment but when I check my bookself later I am sure more will make the list.

The Book of Swords and The Book of Lost Swords - Saberhagen

I'm going to cheat and put them in alphabetical order, since I can't decide.

Chalion series - Lois McMaster Bujold
Chronicles of Narnia - C. S. Lewis
Codex Alera - Jim Butcher
Dresden Files - Jim Butcher
Earthsea - Ursula K. Le Guin
Kushiel's Series - Jacqueline Carey
Memory Sorrow and Thorn - Tad Williams
Newford - Charles de Lint
Riddle of Stars - Patricia McKillip


One of these days when I'm in the mood to read something with ornate language and tons of world building I'll have to try to finish reading The Lord of the Rings.  Someday.  I promise.

I'll save a spot for it.

A Song of Fire and Ice

The Warded Man series by Peter Brett

Those are the only fantasy books I've liked so far. But just started Naomi Novik's Temeraire series and have others on my "to read" list.