What people forget to mention is when they have read a book. I read the Selfish Gene when I was a teen and it left a lasting impression. It was published in 1989. How the Mind works was published in 2011.
Reading the Selfish Gene today as an adult, when you've probably read a dozen similar books already, is not going to have the same effect. It's going to be pretty boring. That's why asking for book recommendations is flawed to begin with.
Dawkins is not an original researcher. He is wonderful at synthesizing research and writing eloquent popular books.
The importance of The Selfish Gene is to write a correct summary of the neo-Darwinian project. In the future (perhaps even now), it will be more famous for the coining of meme (in an appendix IIRC).
However, The Extended Phenotype is a remarkably original exposition of important (then) contemporary frontiers of Darwinism. It is a powerful idea, powerfully described.
It is certainly his most important original contribution to the literature. And a beautiful book. True and convincing. It will change your view of the world. There is no higher praise.
"The God Virus: How Religion Infects Our Lives and Culture" by Darrel Ray follows in the footsteps of The Selfish Gene to certain logical conclusions about clusters of related memes/concepts (specifically: how religion(s) formed and evolved as clusters of overlapping concepts)
Reading the Selfish Gene today as an adult, when you've probably read a dozen similar books already, is not going to have the same effect. It's going to be pretty boring. That's why asking for book recommendations is flawed to begin with.