Re: so, how many of top 100 SF/Fantasy books have YOU read?
If you are interested in alternative history, you should look at Harry Turtledove's books. He is probably the most prolific (and popular) American writer in this genre.
I have a problem with some writers. If you want to give scifi another try, read Heinlein's Starship Troopers for a little dose of politics with your scifi. Heinlein is a prose master and his words leap off the page