I tend to agree with above poster, that no trait is the absolutely best...
My tiers
1. Fin , Cre , Org , Phi
2. Chm, Agg , Exp, Ind
3. Spi , Imp , Pro
My tiers depends alot... I tend only to wonderwhore unconciously, and is always punished for it, so I find Ind and Phi sinking lower and lower in my opinion... A shot at my tiers would be:
1. Fin, Chm, Imp, Org
2. Cre, Agg, Exp, Spi, Pro
3. Ind, Phi
Financial is a very good trait in most games. Especially because I'm a loser at SE. Charismatic is awesome for the happiness, and the XP bonus for units are awesome aswell.
Imperialistic, quite frankly, should maybe belong in 2nd tier. But the bonus on settlers is awesome in some games. Rather alot of games.
Organized is a very passive bonus, and is very hard to feel unless you're not playing with in, in which case you really wish you'd been Org. Maybe belonging on tier 2 aswell.
Creative is good for early borders and cultural defense. It has lots of cheap buildings for happiness midgame.
Aggressive is a rather plain war trait. It is perfectly possible to wage war without it, and I tend to steer clear of it. I don't wage war enough in enough of my games for this trait to reach top tier.
Expansive is annoying. Its biggest strength is
midgame, and cheap granaries and workers early on. Not a gamebreaker.
Spiritual is handy. It's not a gamebreaker. It's the diplomats trait, and I tend to choose it if I want a "smooth" game, because anarchy is just so annoying, watching your entire economy halt!
Protective can be good, mostly lategame. Do I have to draw attention to Churchill's Redcoats? These guys are massive. A barracks, two war civics, and Pentagon = Drill IV CGI riflemunsters out of the gate.
Industrious is... A rather overrated thread, imho. The best thing about it is really early game where it actually means the difference between getting a wonder and not getting it, and for the forges.
Philosophical is a very niche trait. It is good for SE, which I suck at. Hence lowest tier.