Do people who once actually existed count, if they have been used as a fictional character at some point? Because if so, then the first person I'd drop a line in a zombie apocalypse would be Nikola Tesla and his freaking death ray, that's who. Kinda hard to argue with someone who can rip physics a new one.
If not, then I was gonna go for Tony Stark -- or, seeing as that was promptly ninja'd, James Sunderland, if anything just to try and teach the guy how to swing a plank of wood without pausing to think about it for ten seconds beforehand.