Short version: navy jackets (and gray slacks to go with them) are amazing.
I was sitting in a cafe today, drinking coffee and occasionally glancing at one of the baristas, and realized that I wear navy jackets (with gray pants no less) more than anything else. I'll occasionally wear navy jackets with brownish pants. I have 3 solid navy jackets (slightly different textures/buttoning stances/pockets) and am looking to pick up a fourth (DB). I have 5 pairs of gray slacks (again variety of fabrics/textures/shades). Most of the pants can go with most of the jackets. This plus brown shoes gives me something that never looks terrible provided the shirt and the tie go well together. The only limiting feature of this is that it restricts what I can do with blue ties (which is my favorite color for ties).
A few people have mentioned "growing beyond" navy jackets and gray slacks...but it is beyond me why they would want to. I think that there is enough which can be done with shirt/tie/ps/shoes as well as subtle features of the jacket and gray pants themselves that the look won't get old.
Again, short version: I love navy jackets.