I've read CS Lewis' Narnia books aloud to several girlfriends and my children. Makes me smile just thinking about them.
I've always been a fantasy and SF fan, but only if it's literate as well.
IMO, the best "fantasy" written to date is Robert Jordan's Wheel of Time series. Personally I'd vote it the best English language fiction written to date, period. I've read most of the books three or more times, always finding new marvels. And I almost never read fiction more than once.
Jordan died last year, apparently without finishing the series, but the eleven or twelve volumes he did finish will, I believe, stand the test of time. It's the only fiction I brought with me when I left the USA.