So different roleplaying games have different means of casting spells and invoking unearthly powers beyond mortal kith. But which systems of magic and spellcasting do you prefer, and for what reasons?
1)
The Vancian System. Named after Jack Vance (who apparently had a lot to do with this), the player chooses a specific selection of spells and can only cast spells from that assortment until the time comes to replenish those spells. Aside from Level-based power grades and randomized effectiveness, the spells must manifest as their descriptions dictate; a Wizard can't tone down a Fireball spell and use it to burn through the ropes binding him without burning his face off, as an example.
Games Featuring Vancian Magic: Dungeons & Dragons — 1st Edition (the Cleric, Elf and Magic-User Classes), Dungeons & Dragons — 3rd Edition (the Cleric, Paladin, Ranger, Wizard and various Prestige Classes).
2)
Point Pool Magic. With this system, the spellcaster receives a certain amount of points which can be spent and diverted into a variety of spells. Some games include a point pool for each power level of spell; others include a point pool from which all spells known to the spellcaster may be cast, with more powerful spells having higher costs than trivial spells. As with Vancian spells, Point Pool spells and their effects are typically unalterable.
Games Featuring Point Pool Magic: Dungeons & Dragons — 3rd Edition (Bard and Sorcerer Classes), Vampire: The Masquerade (Disciplines paid in Blood Pool), Werewolf: The Apocalypse (Gifts paid in Gnosis and/or Rage), Wraith: The Oblivion (Arcanoi paid in Pathos); same deals with Vampire: The Dark Ages, Werewolf: The Wild West, Wraith: The Great War and Orpheus.
3)
Wild Magic. A rather freeform system of magic in that the player (and his or her spellcaster) state the intent of the spell; from there, the dice and/or the Game Master — not the player — determine exactly how that spell becomes manifest. The Powers from Beyond can be some rather fickle mistresses....
Games Featuring Wild Magic: GURPS Voodoo: The Shadow War.
4)
Wild Point Pool Magic. Similar to Point Pool Magic, but with the provision that spells can be altered and their effects can be made unpredictable (typically at the whims of the dice and/or the Game Master). Magic can also surge, diminish or even backfire at random. The Sorcerers of In Nomine have a better mastery of this randomness than most, but they too can be struck down if one of their spells results in an ill-timed Divine Intervention.
Games Featuring Wild Point Pool Magic: In Nomine.
5)
Mix-and-Match Magic. With this system, the player's spellcaster has access to a limited number of quirks, details, augmentations and/or limitations for his or her spells; the player chooses from among these modular "pieces" and assembles a spell from there. The spell can manifest as anything within the limits of those pieces; if the spellcaster either doesn't know how to affect left-handed salesmen with his magic or doesn't include that element when composing his spell, then his spell won't affect left-handed salesmen, for better or for worse.
Games Featuring Mix-and-Match Magic: Changeling: The Dreaming, Changeling: The Lost.
6)
Pay-the-Piper Magic. This system allows spellcasters to cast spells only after they sacrifice something or otherwise pay a price of some sort. The quality of the sacrifice affects the quality of the spell; a fiery spell for which a worthless trinket is sacrificed might only create enough fire to light a candle, while a centuries-old family heirloom or a burnt book of beautiful poetry, so sacrificed, might produce enough flame to leave a shogun's palace in ashes.
Games Featuring Pay-the-Piper Magic: Legend of the Five Rings (the Shugenja Class).
7)
Contractual Magic. The spellcaster can cast a spell after entering a contract with a second or third party, who typically must provide some manner of service for either the spellcaster or for someone on whose behalf the spellcaster is acting. The terms of the spell are decided by both the spellcaster and the beseeching party before the spell is implemented, and a breech of contract from either party will either simply negate the spell (at best) or incur a nasty backlash on the transgressor (at worst).
Games Featuring Contractual Magic: In Nomine (the Lilim and certain Princes of Hell), Changeling: The Lost.
Backlash Magic. In this system, there is no fixed upper limit on how many spells the spellcaster can cast, nor is there a price to pay beforehand (though in some cases, a payment or sacrifice of some sort can help). But with every cast spell, there is a chance of the spellcaster being beset with some sort of backlash as the cosmic forces being manipulated by the spellcaster decide to fight back. The form of backlash varies by the game; invoking magic in Call of Cthulhu risks tearing the fabric of the spellcaster's Sanity and plunging the mage deeper into crippling madness as the spellcastings themselves force the mage to court or confront Things Which Should Not Be, while accumulating Paradox in Mage: The Ascension can assail the mage with any malady from a mere change in eye color to the complete obliteration of the mage's existence — perhaps even including the erasure of people's memories and all other evidence of that mage's previous existence — depending on how much Paradox has been accumulated.
Games Featuring Backlash Magic: Call of Cthulhu, Mage: The Ascension, Mage: The Sorcerers Crusade, Wraith: The Oblivion (with use of certain Angst-inflicting Arcanoi), Demon: The Fallen (whose casters run the risk of further Torment and the demise of their higher selves).
9)
Magic-Is-Just-Another-Superpower Magic. While magicians are still more powerful than mortal kith and kin, they don't quite stand out so much when they stand in a field of radical scientists, ultratech bodysuits, giant robots and bona fide gods. Doctor Strange can cast all the spells he wants, but he might still find the Incredible Hulk — with his powers spawned of nuclear physics — to be a worthy foe.
Games Featuring Just-Another-Superpower Magic: Marvel Superheroes.
There may be more games with alternate magic systems which I've overlooked; feel free to speak up and mention them if that's the case.
So which system do you little mages prefer?