I must bring in some more:
- a man-made universe "The Way" in Eon by Greg Bear
http://en.wikipedia.org/wiki/The_Way_(Greg_Bear))
- The first universe that really got me started - The Dune universe by Frank Herbert
http://en.wikipedia.org/wiki/Dune_universe
- The Night's Dawn Trilogy by Peter F. Hamilton - great space opera universe with multitude of [Human] civilizations, colonists, sentinent habitats in space, ....
http://en.wikipedia.org/wiki/The_Night%27s_Dawn_Trilogy
- last but not least I will mention in this post is The Otherland series by Tad Williams.
http://en.wikipedia.org/wiki/Otherland
This is great, great adventure that takes place mostly in man made worlds created inside virtual reality simulators. The computers, as you will find out are powered by ... No. No spoilers ... ;-)
If you look up when the series was written, Tad Williams is really quite prescient about the future of Internet, the technology, ...
I really, really enjoyed all four really thick volumes.