Well, after getting into my first game (I'm a casual civ player who never really mastered Civ III - Civ 2 on the other hand...) I'd say Spiritual rocks for beginers because of the lack of penalty for switching civics..
don't like the cost or result of your new civic - well, no anarchy! and anarchy just bites...
I'm playing Aztec for my first go around on Noble ... and I am holding my own but looks like I am headed for a long-term loss to the Egyptians. Without the free switching of civics I'd probably be in a lot more trouble. I'm not sure how usefull aggresive really has been as I'm not that offensive of a player.
Have fun!