What is your favorite character-generation system (tabletop or CRPG), and why? Is it a class system (D&D), a point-buy system (GURPS), or something in between (NWoD, with point-buy within roles)?

In whatever system you like, how much does your class or primary ability set define you? If I tell you that I play a Rogue/Fighter named Coric in a D&D game, that might not tell you everything about his character, but it probably tells you a lot. If I tell you that my wife played a Dedicated/Strong character named Balam in a d20 Modern game, that tells you considerably less. If I tell you that my wife plays an animal mimic in our Mutants & Masterminds game, that tells you almost everything.