[gwsfox]

I would have to go with....
A form that is comfortable on two and four legs (can stand and walk upright, but still be able to move naturally on all fours). The form needs to be wolf like (snout, fur, ect). Tail would be preferable. I do like the full moon being the trigger for the transformation, but some others can be thrown in as long as they make cense (sex, mental instability, ect.)
Mentally, wolf with some human traits. Almost like a mirror of the human with some wolf traits. Behavior after change is like that of a wolf during winter (owning your own slaughter house helps you there). Unless threatened will not attack some of the times. Some. Also, Silver is OK to touch, but will burn on contact with blood (from the werewolf).
As far as werewolves in films go .....
The only one I really liked was An American Werewolf in London. Everything else was either OK or needed to be burned.