All the anime I've seen, in rough order of preference. As usual, the exact ranking gets more arbitrary as the list goes on.

Excellent series with no Letterboxd entries:
Legend of the Galactic Heroes (1988)
Tenchi Muyo! Ryo-Ohki OVA 1 & 2 (1992)
Oh My Goddess! OVA (1993)
El-Hazard: The Magnificent World (1995)
Colorful (1999)
Fate/Zero (2011)