I know the name of this thread is a little vague, but I've been thinking a bit about classic classes that everyone role-plays the same way, and how to change it to be very different. I've only got a few ideas so far, but I'm sure others have some really unique ideas. I've found it's somewhat hard to make traditionally evil classes good, since romanticizing evil is already done so much, so the ones I've thought of are more traditionally good or good-intentioned classes going evil. Here's the (good, as opposed to average) one I have right now. I've thought of a couple others, but none of them are good enough to warrant posting here.
The Wizard Slayer is a class that most people role-play very similarly. (for good logical reason) A strong wizard hating (for some reason, whether it be they lost family to them, believe they are beings of chaos that endanger the world, or even jealousy of the wizard's powers) warrior, generally of Good or Neutral alignment. Now meet my twisted WS...
Wizard Slayer/Mage Multi Class: (I'm ignoring legality in deference to how interesting it is)
This Wizard Slayer is no hater of magic, but rather a hater of other mages. He took up the art of wizard slaying as a way to further his own power, to "be the best" whether by talent or by eliminating the competition. He would probably be Chaotic or Neutral Evil, and would slaughter another mage as soon as he met them. He is a truly merciless killer, bent only on his own success.