This thread is relevant to my interests - one of my preferred pairs of trousers is a set of navy blue moleskins. I have worn them with green corduroy and grey herringbone wool jackets, and even a Gieves hacking jacket in a rather 'out-there' green and pumpkin-coloured check.
I find it all actually comes down to your choice of shoes and belt. A good idea, for example, is a brown leather belt with a pair of dark brown brogues. Brown acts as a good 'bridging' colour which allows you to wear a grey/green/tweed jacket on top. The end result is a pleasing tritone earthy/country/naval palate. When it comes to shirts, blue trousers tend to 'demand' a blue shirt, but I would always stick to a stripe pattern or a check at a stretch; plain blue-on-blue doesn't work so well.
Black shoes necessitate a dark grey or even black jacket for the sake of balance. But you run the risk of looking like a chimney sweep. I have to say I usually avoid wearing black footwear with navy blue trousers for this reason.