What's your favorite spellcasting system?

[Plane Sailing]

Maybe too late to the party to be any use, but some other fun options I've seen

Monte Cooks Arcana Unearthed, where low level slots could be weaved into higher level slots, or high level slots unravelled into lower level slots, and there were also 'heightened' and 'reduced' versions of each spell built in.

In the late 70's there were lots of klutz systems around - spells had a failure chance (%) depending upon how powerful the spell was and how many times you had already cast it. If the spell failed, you checked again for a potential backfire.

I'd add another vote for Runequest, which was a neat system (stackable rune magic and power point based battlemagic)

 

[Particle_Man]

I've never been a big fan of D&D's Vancian spellcasting system, so I'm wondering what other RPGs out there have "better" or at least significantly different spellcasting systems than you can find with D&D. I'm sure a lot of things have been tried in the past, but what I guess I'm most interested in hear which systems you thought:

A. Were the most unique.
B. Were the easiest the play.
C. Made the most sense.

Warlock Invokations for B. The no paperwork magic-user from Complete Arcane is easy to use and design.