Three Worlds Collide (Metaethics, moral relativism, etc)
http://robinhanson.typepad.com/files/three-worlds-collide.pd...
The Metamorphosis of Prime Intellect (Thinking machines, brains-in-vats experience machine, a world without death) This one is my favorite of the three
http://localroger.com/prime-intellect/mopiall.html
The Last Question (Thinking machines, the end state of a universe full of technologically powerful beings)
http://filer.case.edu/dts8/thelastq.htm
Not as relevant as the previous three, but still brain tickling (and not as long):
Relevant scene from Star Trek: The Next Generation (Episode: The Measure of a Man) http://www.youtube.com/watch?v=3PMlDidyG_I
Let's Help Germinate This Seed http://www.thrivenotes.com/lets-help-germinate-this-seed/
My main criticism is that it simply assumes the point it sets out to make (SPOILERS: basically that if you can't die and anything is possible, life would have no meaning). It really doesn't do anything to show why that'd be the case.
It also really fetishises extreme violence and, to a certain extent, incest. (My beef is not with the fact that it involves those things, but with the way that it handles them).
If you're looking for something with similar machine-intelligence, fairly limitless possibilities, and the like, I think Greg Egan's Diaspora is a far superior treatment. http://www.amazon.com/Diaspora-Greg-Egan/dp/0575082097
Anyway, the story appears to be reproduced without permission in violation of copyright.
I believe it's better read merely as food for thought, not as a philosophical treatise.
At code review one hacker guy
Was asked to relax, or to try.
"I'm not naming names,
But all's fun and games
Until someone loses an i!"
(I felt like responding this way just because Asimov wrote limericks.)