Black would work fine. It's a geek interview anyway, not a fashion magazine, right ;~D
What size are your feet?
I wear 9s.
I suppose if navy would really look a lot better, I might be able to locate a Payless or Super Shoes (do you have those out here?) in the morning and run out. Bet I could find something really basic for even ten bucks or so, huh? Would involve *town*, though.