i've put in
bold the ones i use nearly every game!
Vitalise - very difficult to get a result out of. Zothen should be able to use it to get some of the team's vitality up, but its rare to see it being effective.
Warpower - the first/only spell i am for with my Warrior or Adventurers! Can massively increase the amount you are hitting enemies for, so i always use it.
Renew - much like vitalise, you can see it 'attempt' to restore some HP, but with little effect.
Begile - supposedly helps you get bet bargains in trading. since i dont do much trading, i'm not so sure. I'd imagine a high-level Megrim casting it on a low-level trader might yield some results (?). I guess Baldrick would be a good option to use this, as he should have high Charisma already.
Protect - Fantasic spell. Armour / Antimage / Deflect , all as one. Definately my 'defensive' spell of Extended Levels.
Enhance - Warpower again, only more effective. 1000+ Damage hits can happen with this
Restore - You are joking right??? Vivify + all HP/Vitality/Spell Points restored... you need never sleep again!