After playing 0.9.1 more, I get highly annoyed with traveling with tugs in my fleet to keep my speed high. With less income, Erratic Fuel Injector, and more expensive ships and colony building, fuel costs are not negligible, and I think I will start grabbing Navigation in my future games (or maybe my current game since I have unspent points due to decision paralysis), even if I need to give up Fighter Doctrine or Planetary Operations to do it.
With Navigation 3, I can either knock off two tugs from my fleet or remove Augmented Engines from my slowpokes and give them better hullmods. In a way, Navigation can indirectly boost combat power by removing either two tugs from the fleet (more combat ships) or Augmented Engines (stronger cruisers and capitals).
I like to have all three colony skills like the important NPCs (e.g., Kanta, CEO Sun), but if I do this, then either Planetary Operations, Fighter Doctrine, Navigation, or a combat skill must go (and I still have slightly less combat skills than max level officer if I give up a fleet or campaign skill). Before anyone says alpha core, I really dislike dealing with Pather cells, and being able to have maximum colonizes without being bothered by Pathers is really nice.
P.S. I visited some really huge systems, and at least one of them was colony worthy (in 0.9.1 standards). I probably would be highly annoyed if I need to travel far to a jump point and/or through nebula every time I need to return to my home base, so in such a game, Transverse Jump would be really handy.
In my current game, there is an annoying huge system with only one jump point and no planets, and pirate bases spawn there recurringly. This is probably one system where I really want Navigation. (I did not get this kind of system to slog through in my earlier 0.9 games.)