Here's my quick re-hash of the usefulness of the Tier 1 spells, 0 being completely useless and 10 being wicked-awesome (note this reflects my playing style as well as objectivity):
9 Haste (would be a 10 if not for micromanagement)
4 Dance of Blades
4 Raise Skeleton
1 Escape (not 0 only because of Amurite assassins)
1 Wall of Stone (more like a 0.5)
8 Enchanted Blade (would be higher if not for micromanagement)
1 Wither
0 Scorch
0 Loyalty
7 Sanctify
8 Charm Person
6 Treetop Defence
5 Courage
10 Spring
Wow. Goes to show how different playing styles influence spell usefulness! Personally, I'd rate them as follows:
7 Haste (Useful, to be sure, but never game-changing.)
2 Dance of Blades (Eh, if I need the difference this makes, I've already lost.)
9 Raise Skeleton (Free permanent units from adepts? Yes please!)
8 Escape (Never lose a spellcaster again, more or less. Also stops sneak attacks in their tracks, when two dozen conjurers pop up in the capital.)
0 Wall of Stone (Culture kills it.)
7 Enchanted Blade (See Dance of Blades, but permanency makes it worthwile.)
0 Wither (I'd rather kill them.)
0 Scorch (I think that went to Sun? I'm not into sand lions, so this goes unused.)
6 New Fire I spell (Massive micro-free deforestation, yes please.)
5 Loyalty (If nothing else, because it makes werewolves and other enraged units usable.)
2 Sanctify (Meh. Too little impact to prevent the counter from going up once it's started.)
2 Charm Person (Handy, but only when I'm much too weak to handle whatever needs charming - I'd rather deal with the problem now, if possible.)
2 Treetop Defence (See Dance of Blades.)
7 Courage (Just plain good, and attacking dragons requires it.)
8 Spring (The only counter for deserts, of course it's useful.)
0~9 Fair Winds (If I'm using boats, it's a 9. If not, a 0.)