Okay, going down the list...
Hobberdy Dick -- never even heard of it...
The Hobbit -- a lovely book, not as good as LotR, of course, but still fun
The Books of Wonder -- It's Dunsany. It's good

Tales of Averoigne -- Smith is very atmospheric, Old School Gothic (a la Byron and Radcliffe) mixed with post-WWI sickness. Disturbing in some ways, but a lovely read.
The Book of Three Dragons -- never read
Watership Down -- may all the powers preserve me from reading anything by Adams again; both this and
Shardik bored me beyond tears.
The Night Land -- never read
The Face in the Frost -- never even heard of it
A Wizard of Earthsea -- one of the quintessential works of fantasy fiction, a lovely meditation on the difference between the ability to do a thing and when should actually act, beautifully written, a world that I would love to turn into a game, I cannot say enough for this whole series
The Dream-Quest of Unknown Kadath -- probably my favourite Lovecraft work, obviously his nod to Dunsany. Weird, wild, and very, very good.
The Worm Ouroboros -- Another pre-Tolkein bit, it is strange, at times stilted, and very atmospheric; this is the grandfather of Tanith Lee's writing
Bridge of Birds -- I am a rare soul, in that I loathed this book. Didn't bother with the sequels.
A Voyage to Arcturus -- Never even heard of it
Silverlock -- tried to read it when it came out in paper, never finished it, thought of going back to it many times but kept putting other books ahead of it
Fafhrd and the Gray Mouser -- fun stuff! I love these two! They don't always win, but they rarely are down long enough to really hurt. It's all about Issek of the Jug!

Collected Ghost Stories -- Mixed bag (as with all collections of short stories), but generall quite excellent
The Forgotten Beasts of Eld -- Never cared for McKillip either...
The Well at the World's End -- This is very Old School, in that Morris was essentially trying to bring back the Middle Ages into Victorian England. An interesting read, but very stilted by modern standards.
As with all "Best" lists, I have my agreements and my disagreements, but overall, I'd say this is a decent overview grouping.