The Doctor from Doctor Who, Optimus Prime (the original, not any of these craptacular imposters borrowing his name), or DCI Gene Hunt from Life On Mars (and soon Ashes To Ashes).
Why? Well, I like the Doctor's quirky, yet occasionally badass nature, I think Optimus Prime is someone I could aspire to be like, morality-wise (although Megatron is also an influence, paradoxically ). And DCI Hunt is just so gloriously offensive about everyone and everything that he makes me laugh every damn time I see him.
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Why so serious?