I´m quite traditional in that aspect, there´s nothing I like quite as much as navy blue with white. So...naval.

Silver is another great combination. I love silver, and it looks great with navy blue, kinda like a starrry night. Whoever says silver works can say that light gray does as well.
Also, black, though of course then you run the risk of the whole coord being TOO dark, you know? Oh, gold is also a nice color, like other girls have mentioned.
I´ve also seen navy blue combine with off-white/cream, but that´s kinda rare, and sometimes it looks a bit weird.