I would much spend time with a male celebrity, generally because they appear more "interesting", you hardly see females in the things I enjoy plus I'm already dating someone so I don't need to meet any hot chick actresses.
The thing is, it'd be awkward to send a day with either, I don't get along with people I don't know (normally shy away) so it'd kinda suck no matter how cool an idea it sounds, but if it was something like meeting Gabe Newell and spending a day in Value, it'd be down for that.
But yeah, the answer you really want is in the first paragraph, I guess.