My suggestions:
Shichinin No Samurai ( unfortunately a remake is in progress scheduled for 2014, so go and see this now if you haven't already)
Rashomon
and of course Mononoke Hime

Are
Rashomon and
Seven Samurai your favorite Kurosawa films? Which Kurosawa films have you seen? My favorites are actually
Red Beard,
Seven Samurai,
No Regrets for our Youth, and the
The Idiot. Have you watched any films from the other masters of Japan's golden age - i.e. Ozu, Naruse, Mizoguchi, Kobayashi, or Kinoshita?