[ddwkc]

Legend of the Galactic Heroes is a must see if you are truly talking about AAA titles.

Also seconding and adding to what I consider triple A:
-Monster
-Mononoke
-Juuni Kokuki
-Haibane Renmei
-Cowboy Bebop
-Seirei no Moribito
-Mushishi
-Dennou Coil
-Kino no Tabi
-Fruits Basket
-Princess Tutu
-Planetes
-Rurouni Kenshin OVA
-Ghost in the Shell TV series
-Ghibli movies

I don't consider those triple A (double A and a half), but they are must see:
-FLCL
-Evangelion
-Trigun
-Azumanga Daioh
-Ouran High School Host Club
-Serial Experiments Lain
-Fullmetal Panic series
-Akira
-the original Gundam
-the original Macross

Must see for cheer fun factor:
-Toppa Tengen Gurren Lagann
-Eureka Seven
-Last Exile
-Hellsing OVA
-Elfen Lied
-basically everything else already said

I will add:
-Akagi
-Kaiji
-Terra e
-Escaflowne
-Irresponsable Captain Taylor
-Victorian Romance Emma
-Kaleido Star
-Hikaru no Go
-Hajime no Ippo
-Now and Then, Here and There
-Fantastic Children
-RahXephon