I had a fair amount of success with the Beckoning in my last game, but it's a very situational spell. In my case, AI Vanheim had a couple of fortresses in forest provinces that it was using to build an army. So I had a couple of enchantresses with Treelord Staves, Rings of Sorcery, and Spell Foci who just pounded away with Beckoning every turn. POOF: No more army buildup.
For commander-killing spells, my favorites are: Infernal Disease, Earth Attack, Wind Ride, and Winged Monkeys. For some reason, Winged Monkeys doesn't seem to work very often, but it's still fun. I mean, c'mon! Winged Monkeys?! Who doesn't like Winged Monkeys!
