What helps me from time to time are books by Buddy Scalera. The three that I have are called, "Men and Boys," "Women and Girls," and "People and Poses." These books are more so models photographed in action poses, they also include a CD that features additional content not shown in the books.

"Making Comics" by Scott McCloud is also a good one for how to draw comics.

I found a lot of these at Borders, however, a lot of them have closed so now it's either Barnes and Noble or Amazon.com.

I also use a lot of the video game art books for references as well, such as the Art from Borderlands 2. I'm trying to get Bioshock Infinite's art book.

Thanks for the recommendation, I'll look into it.

I also agree about the video game art books. I have a few myself that are really good: Assassin's Creed, Fable and Halo. I'll have to look for the Borderlands one.