spore is a good game. however, i found that in all the stages you are constantly befriending or killing off other creatures. but i love creating creatures and vehicles.
Spore - I have a love / hate relationship with it to be honest. I played it through the first time and enjoyed myself and I spent hours on the space stage just exploring but then the game quickly became repetitive and I havent played it much since. Interesting game engine with lots to offer but when you look at it from a critical point of view, its just a mashup of minigames rolled into one.
As for the expansion; I think i'll wait for some solid reviews to come out before I part with my money this time.