Going with the "no-frills" approach, I basically just copied my Criticker list with a few minor tweaks:
1.
Sita Sings the Blues (2008)
2. Wallace & Gromit in The Wrong Trousers (1993)
3.
Tale of Tales (1979)
4. Wallace & Gromit: The Curse of the Were-Rabbit (2005)
5. Princess Mononoke (1997)
6.
The Mascot (1934)
7.
La Poulette grise (1947)
8.
More (1998)
9.
Begone Dull Care (1949)
10. Kiki's Delivery Service (1989)
11.
Billy's Balloon (1998)
12.
Cat Soup (2001)
13. Fantastic Mr. Fox (2009)
13.
A Poet's Life (1974)
14. Spirited Away (2002)
15.
The Cameraman's Revenge (1912)
16. Wallace & Gromit in A Close Shave (1995)
17. Fantastic Planet (1973)
18.
Une nuit sur le mont chauve (1933)
19. Mind Game (2004)
20. WALL·E (2008)
21. Only Yesterday (1991)
22. A Grand Day Out with Wallace & Gromit (1989)
23. Chicken Run (2000)
24. Whisper of the Heart (1995)
25. The Illusionist (2010)
26. Toy Story 2 (1999)
27. Grave of the Fireflies (1988)
28. Toy Story (1995)
29. Wallace and Gromit in A Matter of Loaf and Death (2008)
30. A Charlie Brown Christmas (1965)
31. When the Wind Blows (1986)
32. South Park: Bigger, Longer, Uncut (1999)
33. 5 Centimeters per Second (2007)
34. Fantasia (1940)
35. Fantasia 2000 (1999)
36.
Kataku (The Demon) (1979)
37.
Ward 13 (2003)
38. My Neighbor Totoro (1988)
39.
The Junky's Christmas (1993)
40. The Thief and the Cobbler (1993)
41.
Bathtime in Clerkenwell (2003)
42.
Hanaori (The Breaking of Branches Is Forbidden) (1968)
43.
The Insects' Christmas (1913)
44. Waltz with Bashir (2008)
45. The Castle of Cagliostro (1979)
46. Persepolis (2007)
47. Snow White and the Seven Dwarfs (1937)
48.
Lily and Jim (1997)
49. Yellow Submarine (1968)
50. The Adventures of Prince Achmed (1926)
I left off Looney Tunes because I feel like I need to rewatch/re-rank a lot more than I have. Right now it'd just be all 1957 stuff. Maybe the next time we do this I'll prioritize some Looney revisits.
I'm not super-psyched about this list, to be honest. There's some stuff on here I love deeply, but clearly I need to watch a lot more animation. Embarrassingly heavy on Ghibli, W&G, and only because I watched them fairly recently, Kawamoto and Starewicz. I'm surprised I have Snow White ranked this high, but I couldn't find anything I'd rather put there.