Majoru Oakheart
Adventurer
I was going to use Zedd as an example as well. I like him as the archetypical D&D Wizard.
He can cast a number of very powerful spells but they require concentration and magic words, they can be interrupted simply by distracting him and he can't finish them. The more powerful of them require special components and take longer to cast.
However, at the same time he appears to have 2 nearly at-will spells that he uses throughout the series: Wizard Fire[the ability to shoot a column of fire](which all Wizards appear to have as an at-will ability in this universe) and the ability to knock people backwards. He often uses both repeatedly in the same battle.
I've always felt like this model seemed appropriate for D&D. I think Zedd would have felt very out of place if he'd started using a crossbow or darts when they were in danger.