I think that you are probably close to being right about humans being near the top, at least homo sapiens. I do think that there will be something that transcends us. IMO it needs to be something that lacks some or most of our psychological evolutionary adaptations, decreased physical limitations, fewer physical requirements or perceived needs (living space, food, atmosphere and temperature limitations, accoutrements, emotional fulfilment) increased lifespan, greatly increased intellectual ability, improved memory storage capacity and recall. I don't just mean Gattaca like either nor will eugenics be necessary, well hopefully not necessary.