Cover art---questions!!!?

Question:

Cover art---questions!!!?

I've just finished my first novel, and now i'm focused on the cover. Here are a few questions for you all:
What are some books with the most eye-catching covers
What seems to be the best form for a cover? (photography, drawings, etc.)

Best Answer - Chosen by Asker:

What kind of book? The Amber series was good to me.