[CholeraJoe]

In the OotP movie, Ginny's patronus was a stallion. Since neither hers nor Ron's were mentioned in the books and JKR revealed in an interview that Ron's was a Jack Russell terrier, that detail for the movie came straight from JKR.

I thought it a little humorous that Luna's patronus was a hare, a well known crazy character from "Alice in Wonderland."

[Bear_in_RoseBear]

Ron's silver terrier does appear in DH, when Harry, Ron, and Hermione are trying to get past the Dementors on their way to the Shrieking Shack.

Heh, a stallion strikes me as being a very "girl" sort of Patronus, knowing how often girls seem to love horses. As for Luna's hare, there are also the old sayings "wild hare" or "crazy as a hare", either of which could apply to Luna. Not to mention her name, taken from the Latin name for the moon, and the root of the word "lunacy". ;)

[JenB]

Possibly unrelated, but neat if it is a reference, in Japanese folklore, where we see a man in the moon, they see a rabbit. So Luna having a hare patronus seems very appropriate.