I think the best way to figure out my answer is not what I like to use when I'm playing at my best, but by looking at what I can't resist doing when I'm playing poorly.
And the answer is clear; Militaristic.
If I *EVER* see an unguarded city, I will pounce on it. If i see Scouts running around, I will hack them down so as to prevent that civ jumping ahead of me in tech via that scout. I'll build barracks too early. I'll try to archer swarm. And many times I *DO* declare war before I'm really truly ready.
Culture comes second to me. I almost ALWAYS, by default, end up trying to for 20K in my capital city. And if I get those cultural buildings on the cheap, all the better. Science tends to be a priority more than religous buildings (as my idea of happiness is conquering the other guy's spice and silk colonies), so Scientific would probably be my #2.
Ironically, I don't often play as Germany or Japan, and certainly not to completion. Due to my third trait, if I'm allowed one, is most certainly Seafaring. I try to play all civs more or less equally, but I always end up going back to the seafaring civs more than the others, over and over. I guess I really like boats. I do not use my naval units particularly efficiently unless I really put my mind to it, but I really do enjoy that extra movement point on a galley.
So, Militaristic/Seafaring/Scientific I suppose would be my personal three-trait civ. Either the Germans building better boats or the Vikings getting fond of reading books.
