Always had a soft spot for Ridcully in the Discworld series. Maybe it's just me, but I've always gotten the impression that there's more going on there than meets the eye. Not saying he's a brilliant mastermind by any stretch, far from it, but everyone seems to dismiss him as eccentric and bumbling, not to mention all that great of a wizard, but I've always figured there's more there.
Plus he's the only wizard I know that's practical enough to know sometimes all you need is a sturdy crossbow.
I remember Raistlin from the old Dragonlance series as well, I loved those books as a kid. Plus in terms or just outright power he's capable of kicking every other fictional wizards ass from Rand Al Bore to Dumbledore to Gandalf and Merlin. He
kills gods. Still have some fond memories of those books, though it's been probably around nine years since I last read em so no clue how well they hold up.