I like the rogue idea, myself. With a high powered class like wizard you are making an already too good thing better. With a low powered class like monk you are just making up for the deficiencies and getting something mediocre.

But a rogue could genuinely benefit from all the stats without becoming overpowered. Good damage, agility, hit points, skills, will saves, and social skills. The perfect rogue!

Factotum would be another excellent choice. They are intended to be a "jack of all trades", so being genuinely good at everything would really compliment the class.