[Metosblat]

I've always held the magic "system" of a fantasy book to be a very important feature. For me the author has to make the magic make sense (the limits of certain things) rather than just making the main character some all powerful sorcerer who scorches everyone at once.

My personal favourites are:
Saidin/Saidar from WOT
Will and the word from Belgariad/mallorean

what are yours?

[Rob B]

Runelords by David Farland has an interesting magic system

The White Gold magic of Thomas Covenant is handled very well

John Marco handles magic (and the cost to the user) pretty well in his Tyrants and Kings books

Saidin/Saidar WoT

[allanon]

The Magic system in the "Riftwar saga".Also
I like the system in "belgariad",WoT and SoT.

[Drewids]

Feist's magic system is probably the best. The way it is explained and described was great, especially when Milamber/Pug was on the Tower of Testing. Jordan's WoT is ok though it isn't described in great detail as in Riftwar. He describes it but Feist makes it come to life and almost believable (as far as you can believe magic). Eddings also did well, Farland's Rune lords was good too.

[chris]

I like mercedes lackeys magic system in her valdemaran books.

[Lani]

I liked magic system from Amber series.
Especially the Logrus vs. Pattern magic.
As well, there is nice magic systems in
Dave Duncan books and I pretty much liked the Skill and the Wit from Robin Hobb's Farseer series.

[Thoughtcriminal84]

Difficult to say which explanation of magic I like the best. To be honest with you, my absolute favorite system of "magic" wasn't even in a fantasy novel, it was in a sci-fi book. (TAking the liberal view of Magic proposed by Arthur c. clarke: any sufficently advanced technology IS magic) I'm talking about the entire spectrum of powers and abilities confered on certain people by the spice melange in the Dune novels. The ability to see the future, the incredible mental feats, the perfection of body, the accessing of genetic ancesteral memory...not exactly "magic" by the same standards of, say Goodkind or Tolkien, but still, very potent (and very fantastical, perhaps more so than a tossing a lightning bolt from your fingertips)
Meanwhile...I can easily tell you which Magic system I hate the most: Terry Goodkind's Additive and Subtractive goobly gook. What a cornball mess of hack work. And most of that magic was "intuitive" which is Goodkind-speak for saying "I don't know why the main character can throw lightning bolts, but when he needs to he can. He's a bad ass, you know...I'm going to post how bad I hate some of Goodkind's work here in a little bit...

[Pluvious]

Yeah, it seems to me that many writers think writing about magic means they don't have to explain it because, well, its "magic" after all. I think the opposite. Show us some details about the mystery, that is what I as a reader live for. Is he pooring over magic volumes, what's in them? How about some myths and legends about magic? Details about gods, other worlds, and the afterlife-that would be helpful. Hackened, unoriginal, fireballs and crystal balls? No thanks.

[Bardos]

I like how magic works in Moorcock's books. Well, he doesn't explain it that much... but how can you explain how multiverse works? -its not for human minds... http://www.sffworld.com/ubb/wink.gif
Now, I think there has to be *some* mystery in magic -not all things said, like mathematics. But many other things must be explained also. Its about balance.