wizard
So I guess it is Evokers that are disproportionally weak?
Ha! Never heard that one before.
I think that, as stated before, its the way you play a wizard that makes them powerful or not. I think the PHB could have done more to explain how to play a wizard. A few points:
1) Older edition wizards had much higher XP required to level up than most classes. With 3E the classes are more balanced, so the wizard seems less god-powerful. Its still the only class that can wipe out an entire town guard at 5th level (with one well placed fireball).
2) In general, wizard direct damage spells do more damage than a fighter can do in one round, and hit more effectively (again, 1st level the exception).
3) Wizards play very differently than most classes. A fighter can attack with his sword every round and hit fairly often. He can take out smaller opponents one at a time or wittle down a bigger opponent. A wizard gets only a few spells per day, but has a chance of taking out many small opponents or one big one with only one spell. Often, the wizard is better at buffing his allies or gettin the party past tricky non-combat encounters. The fighter is easy to pick up and play--attack the bad guy every round. The wizard takes much more planning to play well, and this can be frustrating.
4) Wands. Scrolls. Any wizard above 1st level should have some magic item spells to burn. 50 fireballs in a stick is nasty.
My players mostly go for the warrior types, but the next campaign we're starting will be mostly spellcasters, so it should be a fun change of pace.