Greatest book/series ever!

[Fetzenfisch]

The Dark Tower
Discworld
Gotrek&Felix
Die Kobolde/König der Kobolde

if you are talking in entertaining-good. my opinion as a philologist may vary from that

 

[iwinatlife]

Eisenhorn and Ravenor by Dan Abnett, though hopefully he'll start work on the Lizzie Bequin trilogy soon so we've got a nice trilogy of trilogies.

yay 9 books of awesome

 

[Sehnsucht Engel]

The Wheel Of Time, by Robert Jordan. There's no real competition against it.

 

[James Joseph Emerald]

Neuromancer, William Gibson. Haven't read the two other books in the series though (heard they're unrelated storywise anyway, just share a universe/themes).

 

[Piecewise]

Greatest book/series ever eh? Bit hard to define like that. Do you mean the most influential? The best written? Or simply one that we like the most?

Most influential outside of religion I'd have to go with "Art of war" considering its effects on modern warfare and all the lives it has ended and saved.

 

[Weslebear]

Tie between:

-His Dark Materials Trilogy (as Rhymenoceros said) by Phillip Pullman

-Redwall Series by Brian Jacques

-Mortal Engines Quartet by Phillip Reeve

 

[solidstatemind]

Armor [http://search.barnesandnoble.com/Armor/John-Steakley/e/9780886773687/?itm=4&USRI=Armor] by John Steakley. Simply put, the best military sci-fi you'll ever read.

The Black Company [http://search.barnesandnoble.com/Black-Company/Glen-Cook/e/9780812521399/?itm=10&USRI=glen+cook] and the rest of the BC series by Glen Cook, who is possibly one of the most underrated writers in sci-fi/fantasy. Seriously, you won't go wrong with any of his books.

Cryptonomicon [http://search.barnesandnoble.com/Cryptonomicon/Neal-Stephenson/e/9780060575489/?itm=1&USRI=cryptonomicon] by Neal Stephenson. Math, cryptography, history, social theory and commentary, all excecuted in an approachable style.

William Gibson:
The Sprawl Series:
Neuromancer [http://search.barnesandnoble.com/Neuromancer/William-Gibson/e/9780786540396/?itm=1&USRI=neuromancer]
Count Zero [http://search.barnesandnoble.com/Count-Zero/William-Gibson/e/9780441013678/?itm=1&USRI=count+zero]
Mona Lisa Overdrive [http://search.barnesandnoble.com/Mona-Lisa-Overdrive/William-Gibson/e/9780553281743/?itm=1&USRI=mona+lisa+overdrive]

Other works:
Burning Chrome [http://search.barnesandnoble.com/Burning-Chrome/William-Gibson/e/9780060539825/?itm=1&USRI=burning+chrome]
Pattern Recognition [http://search.barnesandnoble.com/Pattern-Recognition/William-Gibson/e/9780786537624/?itm=5&USRI=pattern+recognition]

William Gibson almost single-handedly evolved Philp K. Dick-style speculative fiction into the genre of Cyberpunk. Authors such as Bruce Stirling, Neal Stephenson, Jon Shirley, etc. followed his lead, and games such as Deus Ex, System Shock, Syndicate, etc. were deeply influenced by his work. If you're a fan of SciFi, these books are virtually required reading. It doesn't hurt that he is one of the best wordsmiths you will ever read. Take for example the first line of Nueromancer:
"The sky above the port was the color of television, tuned to a dead channel."

Neuromancer, William Gibson. Haven't read the two other books in the series though (heard they're unrelated storywise anyway, just share a universe/themes).

You've been misinformed. While Count Zero and Mona Lisa Overdrive don't really use the same characters (although Molly is a central character in MLO), they continue the story of the Tessier-Ashpool AIs. Very, very relevant.

 

[Rhymenoceros]

Tie between:

-His Dark Materials Trilogy (as Rhymenoceros said) by Phillip Pullman

-Redwall Series by Brian Jacques

-Mortal Engines Quartet by Phillip Reeve

All absolutely amazing series. I though of mentioning Redwall in the OP but decided against it and now that you mention it Mortal Engines were a great series

 

[Orwellian37]

The Hitchhiker's Guide to the Galaxy

 

[Mass B]

i liked the Artemis Fowl series, the Hungry City Chronicles was excellent as well

 

[Aglynugga]

Hunter/victim - Robert Sheckley - We could probably use this game...
Otherworld - Tad Williams (Dragonbone chair series is also alright.)
What? No Samuria cat? You guyz don leik Samuria Kittiez?
The Borribles - Micheal De Larrabeti
They don't even write this kind of stuff now. Trust me. I mean, Dave Duncan and Barbara Hanbary versus Terry Goodkind and Robert Jordan? Please. This new stuff is pale and a lot of the new fantasy seems to cater towards some strange bdsm fetish. I'm not joking, I can go off on a list of contemporary fantasy novels that are in Chapters, Audrey's...and are one step above consistant rape fantasies, or just so simplistically written for easy consumption that it takes the fun out of reading. I don't care how much brocading a dress has! That's not a character! I don't want to know if they're worthy of being clit peirced with silver or gold! That's not a fucking story.
I blame Dave Eddings and Raymond Fiest, two talented fantasy authors that both deveopled sure-fire methods for producing novels that have now been carbon copied to death by everyone that wanted to bang out a quick book. You can even tell since most of their plotlines are repeated ad nauseum in varition through-out the genre of Fantasy with sometimes barely a name change to mark a difference.
I honestly think the best years for Fantasy where the ninties and eighties. Anyone remember Mercedes Lackey? Fucking elves.
"One doesn't simply walk into Mordor.
So what's the plan then?
Welll...we're going to hike up into these mountains and uh..journey into mordor.
We're walking, aren't we."
On the other hand, if you like mudkipz in your science fiction! Nah I lie, most of the good stuff has already been written and we'll need like a paradigm shift to get any more good stories.

 

[sketch_zeppelin]

It's been said before but Disc World

 

[foxlovingfreak]

The Dark Tower Series is still perhaps the best thing I have ever read. My all time favorite single book however is still House of the Scorpion.

 

[AyenbiteOfInwyt]

Big fan of Artemis Fowl seris, but felt the last one (The Atlantis Complex) was a bit of a let down.
Song of Ice and Fire is definitely up there in terms of Fantasy
Asimov's Foundation trilogy is fantastic
Robert Rankin's The hollow Chocolate Bunnies of the Apocalypse and The Toyminator are good fun (first is far superior though)

Always find myself coming back to Heller's Catch-22 when it comes to my favourite book though. In terms of humour, bathos and pure tragedy, I always find it intensely moving

 

[AwesomeNinjaPowers]

Anything by David Eddings especially the Sparhawk books

 

[RowdyRodimus]

Yes, I'm a guy saying this but my all time favorite series of books is the Ramona Quimby series. I think I started reading them when I was five or so, and now am in the process of reading them to my niece.

But my all time favorite single book is IT by Stephen King.