To me, the best rule system ever devised is OD&D. Amber Diceless is pretty darn sweet, too.

The best setting ever done is Middle-earth, although if we're talking gaming-only setting it has to be Blackmoor as presented in the FFC. Lankhmar is a pretty close choice as a gaming setting, even if it's also a literary setting. Argh. So hard to choose....

The best adventure module is hard for me to pinpoint since I don't run modules that much. Maybe the G-series by Gygax.

And the best fantasy novels are written by JRRT, Robert E Howard, and Michael Moorcock, based on the number of times I've bought and/or re-read them!