come on! it's gotta be those Hellenistic Greeks, dude!. At least as far as the European Civilization is concerned, Rome was like Greece's child which grew very tall and strong, but it was the bearded father of Democracy and Philosophy who started it all.
Overall, considering the length and quality of their cultural value so far, and their effects still affecting our way of life today, I'd say:
1. Greece
2. Rome
3. China
4. India
5. Egypt
6. Babylon
7. Persia
8. Great Britain
9. France
10 Germany
Closely behind, not in order, USA, Spain, Japan and the Vikings.
Overall, considering the length and quality of their cultural value so far, and their effects still affecting our way of life today, I'd say:
1. Greece
2. Rome
3. China
4. India
5. Egypt
6. Babylon
7. Persia
8. Great Britain
9. France
10 Germany
Closely behind, not in order, USA, Spain, Japan and the Vikings.