Magician

Magicians and illusionists are in Role playing Games, the weak esoteric character that everybody likes to fight against but are scarcely playing.

Why ?

In Role Playing Games, playing a magician is a terrible experience, when you start you have essentially one spell, and very little hit points... which means, that you depend a lot on the group - there's very little chance for a magic-user to survive alone.

The cleric is much better, balancing fighting capacities, and healing spell. But the magic-user are getting powerful only at high levels, and then they're cool to play.

Teleportation, telekinesis, mind control, Wall of fire, Fireball, Magic Shield, they are all pretty impressive spell you won't get until 8 or 9th level.

The good thing about Magic-user though is the mystery that the game master can add to a campaign.
When introducing a complex item, a relic or a scroll, who's going to read and analyze it ... the barbarian ? the thief (also he could in some ways) but usually it's the magician, and then the quest can start.

In "the Hobbit" basically the character of Gandalf, represents that mysterious figure able to save the day, but who is missing most of the time, because he's out there doing some weird quests in parallel, I'd say that Gandalf is a perfect high level magic-user but a non player character. Because he's part of the story, his moves are actually having a consequences on the campaign's plot.

He is the enlightened one - working hand in hand with fate (represented by the game master). 

“When society reaches a stage where property confers rank, where wealth becomes the only source of virtue, passion the sole bond between man and wife, falsehood the source of success in life, sex the only means of enjoyment, and when outer trappings are confused with inner religion…then we are in the Kali Yuga—the Dark Age.”
—     Vishnu Purana, Book 4, chapter 24.

N. PabloTsunami: For its significant power and mystery the magician may be feared and also fear himself and his potential to do harm. Key words to understand this archetype are, intuition, knowledge, confidence, action, creation and mystery. More else clear examples of magician characters are Merlin from druidic legends, Gandalf and Saruman from Tolkien, Lord of the Rings saga, J.K Rowling main character Harry Potter and Neo of the Matrix trilogy.