There is no reason to assume that evolution stops with humans. We will evolve into something different. This might be biological evolution, or something else. The posthumans might be degenerate, or superior. There might be one single successor species, or many of them. The posthumans might remember us, or we are to them just an object of palaeontological research, or merely a legend most scientists don't take seriously.

Posthumans might occur in very different forms. They might be genetically engineered humans. They might be cyborgs. They might be artificial intelligences, either centralized or distributed, residing in computers or networks, or in artificial bodies. They might even be non-corporeal beings. Accordingly, they might be deliberately alien in psychology. If they coexist with humans, they might look down on the latter (`What? You are so primitive that you still believe in flesh and bones?'). In short, these posthumans might be almost deliberately alien! A good collection of ideas for posthuman beings can be found on Anders Sandberg's Transhumanism pages.