There are a few out there who actually look for the evidence and make some interesting finds. But for the most part it is one author stealing from another. I have seen many books on the Annunaki and the Sumerians where the authors are claiming some big ideas. I don't think they realize we are not dummies and know Zecharia Sitchin has been there before with his books.
As for AA, they just keep the same show on and change the main title. "Ancient Alien theorists believe..." I don't think they have come up with anything new in a long time.
I have von Daniken's new book on pre-order but I doubt he will have anything world changing in it.
Philip Coppens was turning into one of my favorites but his untimely death leaves a huge void. He actually wrote many intelligent books on the subjects at hand.