So here's your opportunity. In the comments, leave your top 10 favorite fantasy and/or sci-fi novels or series. They don't need to be in order. Assuming this draws enough response, I'll try to combine all the responses into a real "top 100." I think the TSM audience is a much better population sample for something like this.
I'll go first.
1. The Moon is a Harsh Mistress - Robert A. HeinleinI discovered Sci-Fi at about age 11 - Heinlein's juveniles. When I was 13 or so, I found The Science Fiction Hall of Fame in the school library. That was it. I was hooked for life. Starship Troopers, The Moon is a Harsh Mistress and everything else Heinlein wrote followed. Also Azimov, Clark, etc., though honestly I like Azimov's nonfiction better than his fiction. While Larry Niven and Jerry Pournell are not represented on this list, I do love their stuff. The Mote in God's Eye and Footfall are favorites, I just don't find myself re-reading them.
2. Starship Troopers - Robert A. Heinlein
3. Dune - Frank Herbert
4. The General series - David Drake, S.M. Stirling - the original quintilogy, not the three follow-ons.
5. The Vorkosigan saga - Lois McMaster Bujold
6. The Science Fiction Hall of Fame, Vol. I - this is cheating, but it is a book I re-read, and I went to a lot of effort to get a copy when one I loaned out never came back. This is where I first read Flowers for Algernon, and it is by far not the best story in that anthology.
7. The Hammer's Slammers series - David Drake
8. The Ring of Fire series - Eric Flint & others. I also enjoy the Dies the Fire flip-side of this universe.
9. The Nantucket series - S.M. Stirling
10. The Past Through Tomorrow: A Future History - Robert A. Heinlein. Another anthology, but this one is all Heinlein.
This list represents the books that I re-read on a relatively regular basis - books I've literally worn out and had to replace. I read a lot of other stuff, both fiction and non-fiction, but Sci-Fi is my preferred genre. SF can be anything, from pulp to high literature, bodice-ripper to deepest, darkest horror. Science Fiction is the ultimate "what-if?"
11. Empire of the East - Fred Saberhagen.
So, what are yours?