Gamespy has an article from the D.I.C.E. Summit where Maxis co-founder Will Wright and the team behind Spore talked about the upcoming game.

Although the session proceeded at a pretty quick pace, one of the most important slides of the presentation came pretty early on, as Wright tried to summarize exactly what type of game Spore is. Starting you off as a basic molecule and allowing you to progress through the creation of creatures, cities, civilizations and eventually galaxies, "SimUniverse" would have been an apt title, except, as Wright said, "I'm tired of titles with 'Sim' in them." So up went a slide that showed the eight distinct phases of Spore, and the types of gameplay they most resembled:

Molecular ->> Tetris
Cellular ->> Pac-Man
Creature ->> Diablo / FPS
Tribal ->> Populous
City ->> SimCity
Civilization ->> Civilization / Risk
Terraform ->> SimEarth
Galactic ->> Masters of Orion