Ithlilian, welcome to the forums. :-)
Here are some recommendations for you:
"Sirius" by Olaf Stapledon - it's a classic sci-fi about a dog with human intelligence, written in Britain in the 1940's I think. A thought-provoking and tragic novel which I really should read again, now that I think of it...
"City of Saints and Madmen" by Jeff VanDerMeer - this is a dark fantasy about the city of Ambergris. The book is a collection of writings - some short stories, a few novellas, a "travel guide", a history of Ambergris, and the most hilarious glossary I've ever read - about this alternate reality. It's not an easy book to get into but I found it immensely trippy and rewarding, and thought about it often in the weeks and months after I read it. My next book purchase will be "Veniss Underground", also by VanDerMeer, which gets even more enthusiastic reviews on Amazon than City of Saints did.
"The Diamond Age" by Neal Stephenson - this one is hard to describe, so I'll just advise you to look it up on Amazon! The ending sort of fell apart, but I completely lost myself in this book. The future that Neal Stephenson envisions just blew my mind. Hubby recommended this one to me and I didn't think I'd like it (I don't usually seek out sci-fi or fantasy, but he's a huge fan), but I babbled about it to him throughout and I think he wished he'd never mentioned it to me. :-)
"Blood Music" by Greg Bear - nanotechnology gone horribly awry. Sad and beautiful, and only too plausible.
I don't really consider myself a "fan" of sci-fi or fantasy, but it's funny how some of my favorite books fall into those categories...or maybe they should be called "speculative fiction"...