I find Arthur C. Clarke very hit or miss. The first book in each series is good and intriguing, the rest not so much. Rendezvous with Rama was amazing, the rest of the series went downhill very fast.
Anne McCaffrey was a childhood favourite, and my mother loved her books too. Pern went downhill after White Dragon and dragondrums though, and much of her later work is basically her son with her name on the front. He's not a good writer.
David Eddings is still a personal favourite, I'm currently re-reading The Elenium/Tamuli. You can tell when his wife started co-writing though, as the early stuff (Belgariad and Elenium) is a lot less complicated and fun than the later ones (Mallorian/ Tamuli). As a standalone book The Redemption of Althalas is really fun and a great riff on time travel and changing history to put things in place to help when you get back to your own time.
And just to be controversial, I don't rate Lord of the Rings at all. I find them horrible to read despite having a really great story, and much of what a modern writer would consider essential is relegated to throwaway lines. "Gandalf, how did you escape the Balrog?" "I did a thing" OK, moving on."............. "Gandalf, what happened there?" "Oh there was a massive battle that raged for days". "OK sounds like it was a good job we missed it".