A couple of my garters will start climbing the side of their tank trying to get to me the second I walk in the room (they don't do this for anyone else). Most of my snakes don't seem to care what I do until I bring mice in. I think they definitely remember their keepers and may even be curious about us if they're adjusted well to their surroundings, but I doubt they have the mental capacity to think about us when we're not around.
I think my turtle can because we'll walk in and find her on her hind legs watching the door. Even the friendliest snakes seem to forget we exist when we're not in the room though.