Best Civilization-esque building sim games?

[MrPopo]

Have you tried the scenarios? They're pretty goal oriented.

[Xeogred]

I have not... I will have to try them out.

[Ack]

Beyond the suggestions already posted, I'd also suggest Stardock's Galactic Civilizations 2. I've never played the first in the series, which was a remake of a much older game, but the GC2 was phenomenal and allowed for the development of planets, interstellar war, custom alien species and spacecraft creation, culture victories, and some choices for construction of resource production on captured planets. My first game, I led a tech-happy race of alien squirrels in a rampage across the galaxy. Good times were had, and my alien squirrel culture soon spread over the few areas of the galaxy I had not devastated in my attempts to find new planets to harvest acorns for the winter.