ef - a tale of memories (Imo the best drama/romance Anime out there, its combination of beautiful artstyle, perfect musical scores, and a deep plot with great character development made this series a Masterpiece of story telling.
Code Geass - Hangyaku no Lelouch (Season One)
True Tears (Another great drama/romance and the second out of two series of this genre that I scored a 10/10 (the first being ef - a tale of memories)
Clannad (now ef - a tale of memories and True Tears I consider Drama/Romance, Clannad is a great Comedy/Romance with some drama thrown in (the real story is a lot more dramatic than the Anime (although the new Clannad series just started, and it should be on the after story of Nagisa's route, which will be very tragic and dramatic))
2. Ah! My Goddess (Season1, Season2, Fighting Wing, Movie)
3. Rurouni Kenshin
4. Digimon (all series)
5. Ichigo 100% (not like in manga, but the theme song Shine of Voice and Ike Ike really suits the story)