Which spells are the best?

I play as elf, pure mage (no tech or melee), so far I've mastered the schools of Black Necromancy and Energy, I also know Unlock Cantrip (magical thief!) and Minor Healing . My magick is at 80, I think, but I want to raise it to 100 to make spells stronger. But which spells shoul I learn now? I don't want to waste precious points on spells that I won't use. I should also add that I HATE summoning spells (not just in Arcanum, but in all other CRPGs - Baldurs Gate, Diablo...) - I consider it cowardly when someone else does killing for me.

 

I think you mean "Force" instead of "Energy"?

I think you may want to get the first spell of each elemental magic (Fire, Air, Water, Earth). Those spells can modify your stat, and you can cast as many of them as you can maintain - their effects are cumulative. e.g. you can use 3 Agility of Fire and get a great Dex boost.
Also get Major Healing... besides healing a lot of hp, it can also fix crippled limbs and scars. And you'll need Cure Poison by the way.
Fireflash is also good - while your Harm and Disintegrate are powerful, they can harm one foe at a time. Fireflash can do area damage (without harming your own party) and can destroy enemies' armors - soften them up.

Get Teleportation - very handy.

Note that while you can open any locks with Unlocking Cantrip, it's a very noisy spell.

 

Did you bring Temporal - those are pretty good too.

 

Teleportation - a must have!!!!
Morph - not bad in combination with necromancy black.