What's the difference of the Sony Playstation 3 Europian model to that of the Japanese ones?

Answer 1

Japanese versions have better backwards compatibility (20GB and 60GB models have Emotion Engine chip from PS2 - more than 90% of old games can be played). US 20GB and 60GB have it too. Euro versions don't have that at all - old games run on software (around 80% of games can be played, 40GB doesn't have that at all).
Also japanese versions have an extra feature in the menu (for one online service, available only in Japan). Japanese versions have extra colors (white and silver). Dualshock 3 is coming to Japan in November, while other countries will get it only in 1Q 2008.

Answer 2

There is no difference.