When I first started seriously collecting GA (well, as seriously as I could afford at the time), I was looking for Batman/Superman books. A friend told me to look for Wonder Woman instead. He said they were much cheaper in comparison and much scarcer.
They had a long way to go to reach the prices of the other two series, forget about Timelys, just the DCs.
I think they still have a way to go. I don't see prices falling, but I DO see more available than there used to be. I guess the movie woke people up.
The only data I can use is my own collection. This is the only series I'm always trying to upgrade and it's been getting steadily harder, especially over the past year.
I don't really see a drop. I've gotten outbid on a lot of books even when I put in bids that would have easily won last year.