When I first switched to the firebolt spell it was a big adjustment. The advantage was that I could hit things at a distance, but the disadvantage was that it cost a ton more magicka, and it was easier to waste because you could miss, while the flamethrower type spell was much easier to aim.

But once I made the adjustment I came to love it. Once you hit 60 Destruction and pick up the two perks that double your fire damage, along with the dual-wielding spell perk, a two-fisted firebolt will literally blow your enemies off cliffs and out of their socks. It's extremely satisfying when you've got the aim practiced. Feels very mage-like. And then there's fireball, the next level spell. I don't have the magicka oomph to use it all the time yet, but the devestation it wrecks in large groups of enemies is a sight to behold.

But yes, I've also been grabbing the magicka cost reduction perks, and I'm using no-armor mage gear that increases my power and lowers my cost even further. I can't take much of a beating, but honestly, I don't need to. I can kill a giant before it can get close to me. The perk that adds a stun to your two-fisted spells is magnificent. That thing will even stun a dragon.