And his short story "Learning to be me" (I think that's the one) present a slightly more horrifying take on it.

I found David Brin's novel Kiln People to be an fun enough read and an interesting take on thoughts related to human consciousness copying. He uses an entirely different technical mechanism to get the copying, thus allowing a different angle in the thinking.

An interesting animation about this topic by John Weldon:

http://www.youtube.com/watch?v=pdxucpPq6Lc

On the same note, the Asgard race of aliens from Stargate SG-1 were also copies. Later episodes in the series address the same sort of scenario.