I've always gotta throw in a plug for my favorite sci fi novel Blindsight (available to read free on the internet: http://www.rifters.com/real/Blindsight.htm) when I see threads like this.
Blindsight is a very compelling exploration of the idea that there may be different roles of consciousness in advanced intelligence. We know that a conscious decision on say the visual processing loop ends up costing 120ms or so. Why is this a good thing? What if you can have advanced intelligence without consciousness? Some work in AI (and some worries people have about AI) suggests this may be a real possibility as well.
The end result for me ends up being a much more intense feeling of the kinds of varieties of intelligence that may exist in the galaxy, or that we may end up creating ourselves.
Fantastic book, great hard sci fi.
His rifters trilogy was decent too, got a bit wacky in the last 2 books but still a fun read