Anime Essentials..that you haven't seen.

[Vicious]

While we're on the subject, the following is what animeondvd.com considers their essential list. Of course stuff that hasn't been released or is just being released on Region 1 DVD's is not on the list.

Ah! My Goddess The Movie & Oh! My Goddess OVA Series
Akira
Battle Athletes Victory
Castle of Cagliostro
Cowboy Bebop
Crest of the Stars
Escaflowne TV Series
Fushigi Yugi
Ghost in the Shell
Grave of the Fireflies
Macross Plus
Neon Genesis Evangelion
Princess Mononoke
Record of Lodoss War
Rurouni Kenshin OVA Series
Sakura Diaries: Collectors Edition
Serial Experiments Lain
Tenchi Muyo
Urusei Yatsura