Navy is my absolute favorite neutral to wear. (heck, I even included it in my wedding!) It's classic, timeless, seasonless and not quite as harsh as black. Black is difficult for me to rock some of the time because I am so pale. It makes me look a bit goth. And black is more difficult to pull off in the summer. Enter navy! It's the perfect summer (and fall, and spring and winter) neutral.
There are a few colors that basically always go with navy blue. These are what I call the fool-proof colors to wear with navy and these are perfect for summer.