I spent a lot of time searching for and collecting the books in James Cawthorn and Micheal Moorcock's Fantasy: The 100 Best Books. I don't remember how many I managed to find before I got distracted doing other things, 70, 80? I also had the Horror version and that added 100 more titles to be on the lookout for.
If you like that kind of thing, hunting out both the classics and the origins of genre fiction, you should really check out a series by Jess Nevins at io9. It speculates on what the Hugo awards might have been given to if they'd started back in the 1880's rather than the 1950's.