Sorry, i dont think i killed it first post... just seems not too many people are intrested in achievements I guess. I was waiting for a flame on me for saying that.
With the amount of work required for adding achievements with Steamworks, I don't think it is necessary that everyone wants them for it to be a good decision.
I like them

I think it could be fun to chase achievements. Hopefully they'll be mostly based on skill, and not the "Play the game for a million years and get lucky" kind. Here are some ideas, though it's hard without knowing how the game works.
City Conqueror - Conquer 5 or more city states in one game.
Who Let the Dogs Out? - Bring along three war allies against the same enemy.
A Hero is Born - Get xx XP for a single unit.
Send in the Clowns! - Win a cultural victory with at most 3 cities (or something like that).
Everybody's Friend - Get 100% of the votes in a diplomatic election (SP?).
Medieval Space Traveller - Launch a space ship before 1500AD.
We're All Alone - Win a game starting in isolation.
This is my gun - Conquer all civilizations with only riflemen.
The Beginning is the End - Win a game before year 0.
Incan Pride - Win a conquest vicory on the earth map as the Incans.
Hopefully someone can think of more interesting ones than me

I also guess most of these would need a difficulty level and world size requirement as well.