I enjoy using my Icestorm and my Circle of Fire...

I could hardly wait for Word of Death...

I hardly got to use any spells, the monsters are always in my face too soon with the limited view I have of my horizon!
Sad!

I haven't gotten a chance to use any Fiend spells yet but as soon as I get out of the Sunken City, I plan on it!
I already cruised around Cet's Pyramid, I hope there are things left or that will re-spawn there that I can mega-toast!

Incinerate. Flamestrike is useful too but doesn't do much damage at higher levels.

In the immortal words of Beavis & Butthead..."Fire fire heh heh heh..."

Doesn't ANYONE use Binding Force?

I use Binding Force, Freeze and Frost Breath a lot, so that I can paralyse opponents and pickpocket them! Works great when you need money (by selling stuff), skulls, eggs, serpin coins....

Defensive: Bless and Bloodlust. As soon as they go off, I cast them again. I also use Haste and Heroic Might whenever I'm about to have a big encounter.

Status: Call of Home, Create Portal, and Teleport. Don't leave home without them!

Offensive: Naturally all the Storm spells to take out large groups of Monsters. Interestingly enough, Icestorm comes in handy much later in the game when facing demons (except for those ice demons, then revert back to Firestorm.)

Also fun offensive spells: Pain (a must-have and easy to get), Spectral Raven (just don't stand so close to me!), and Incinerate (ditto to emilyh).