If we're talking about hypotheticals, how about George Clooney? He's politically aware, doesn't come across as insane in the interviews he's had re: political issues, and has an unholy level of charisma.
Or, assuming a complete overhaul of the whole 'American born' rule, Arnold Schwarznegger? Fidelity issues might plague him, but from what I hear, he's been an effective governator willing to work with both sides. Also, California is freaking huge, it's practically a country in it's own right.
I don't know anything about Clooney's politics, so no comment there.
Schwarznegger? I don't think so. He wasn't a
terrible governator, but I don't think he could make a good president. I'd rather have him than Bachman or Perry, but that really isn't saying much.