My favourite Anime film so far is
Ninja Scroll
I am not really an "anime fan" but tend to watch the more popular anime films (dont really have time to get into the TV series much) such as
Ghost In A Shell for example.
However recently I have been really getting into the Lupin III movies after watching
Lupin III - Castle Of Caglisostro
I'll post more details on the anime and it's films later on, as it gets rather confusing as up to 5 different production compaines released a film with the character, making searching for it very dificult.
So yeah, anything that's funny, or involves lots of stealthy ninjas killing people gets my vote, but stuff like Naruto is a bit too "childish" for my liking.
The closest I ever got to getting into an anime TV series is the cartoon
Monster Rancher
After watching it, I felt like a young lad watching Transformers all over again, even though I could guess the plot and knew what was about to happen, I was still transfixed.