It's always fun to see that almost everyone has a different approach to the game and like different traits. 
1) Financial
Money rules to world. This trait gives more money. I always feel handicapped without it.
2) Philosophical
Second best tech trait. Really powers up your early game and helps getting those GP's when you need them.
3) Aggressive
My favourite warmongering trait. I feel much stronger and more confident in war when I can rely on stronger offensive troops. And cheap barracks!
4) Organised
Whip courthouses at 4 pop instead of 8! Does miracles for your rexing capabilities.
5) Charismatic
Extra happy and stronger troops over time. What's not to like?
6) Creative
Faster border pops. Win the culture wars over those recources. Flexible city placement. Cheap libraries. Me like.
7) Spiritual
Switch from warmode to teching and peace in an instance. Seventh place for me since I don't switch around so much.
8) Industrious
Seldom build more that one or two wonders in early game. In late game I'm usually so far ahead it wont matter. Cheap forges are neat though.
9) Expansive
Guess it's nice to have cheap granaries and extra health when the industrial age come. Not a trait I play much with.
10) Imperialistic
Meh. I tried this out a few times. The bonuses are just to weak to really make it worthwile. I'd rather have any of the traits
above.
11) Protective
Defensive promotions and cheap castles? I know you can leverage it (read the thread in the strategy section) but as with imp, I'd rather have any other trait.

1) Financial
Money rules to world. This trait gives more money. I always feel handicapped without it.
2) Philosophical
Second best tech trait. Really powers up your early game and helps getting those GP's when you need them.
3) Aggressive
My favourite warmongering trait. I feel much stronger and more confident in war when I can rely on stronger offensive troops. And cheap barracks!
4) Organised
Whip courthouses at 4 pop instead of 8! Does miracles for your rexing capabilities.
5) Charismatic
Extra happy and stronger troops over time. What's not to like?
6) Creative
Faster border pops. Win the culture wars over those recources. Flexible city placement. Cheap libraries. Me like.
7) Spiritual
Switch from warmode to teching and peace in an instance. Seventh place for me since I don't switch around so much.
8) Industrious
Seldom build more that one or two wonders in early game. In late game I'm usually so far ahead it wont matter. Cheap forges are neat though.
9) Expansive
Guess it's nice to have cheap granaries and extra health when the industrial age come. Not a trait I play much with.
10) Imperialistic
Meh. I tried this out a few times. The bonuses are just to weak to really make it worthwile. I'd rather have any of the traits
above.
11) Protective
Defensive promotions and cheap castles? I know you can leverage it (read the thread in the strategy section) but as with imp, I'd rather have any other trait.