The best thing I found in those letters I've mentioned here and here, is a list I made in January 1961 of my twenty favorite SF books. (You can click on the image to enlarge it.) I make no apologies for this list. I still love those books, even #6, Hunters out of Time, which isn't strictly a book but a novel that appeared in Amazing Stories in 1959. Number 9, Starship Soldier, is obviously a reference to the serial version that appeared in F&SF, and I probably hadn't read the novel version in 1961. You'll notice there's a lot of Heinlein on the list. I was obviously a big fan. You might also notice that there are several short story colections on the list. I came to SF reading through short stories, and I read a ton of them. There's one book on the list that I don't remember at all: Harlan Ellison's The Man with 9 Lives. I must have liked it a lot since I put it on the list, and it's embarrassing to me that I have no memory of it. I have a copy, so I'll have to check it out.