I don't see anything wrong with a black tie worn with a navy jacket. If it's a knit tie, I think that's a fairly classic look. Black pants don't provide enough contrast to a navy jacket. When not wearing a suit, you want contrast between jacket and trousers, but contrast is not necessary or really desirable between shoe and trouser. A midnight blue velvet jacket looks nice over black tuxedo trousers, however, since there is enough contrast in the texture. All IMHO of course.