Amazon is happy. So is VISA. Having recently subscribed to Sam Harris' email list, today I got a message plugging his recommended reading list -- which includes suggestions from readers of his books.
Harris often is billed as a "new atheist." However, I see him more as a "spiritual but not religious" sort of guy, where spiritual doesn't mean anything supernatural. More like mindfulness, or making best use of human potential.
Have a look yourself. These are books for people who aren't attracted to traditional religions, yet seek something more... with the something diffusely defined.