In my early teenage I read a lot of fantasy novels, starting out with Lloyd Alexander and C. S. Lewis and then of course went on with Tolkien. The first two i recall as aiming towards young readers and I guess they are great in their own right as such. In some of Tolkiens works lies more deept that still appeals to me as a "young adult" or whatever you call the age I'm now (22).
After these (and a few other in the same manner) quite many of storys I think I nowdays would regard as quite flat, Eddings, Brooks, Williams, Goodkind etc. and having very much the same consepts (a young boy/man grows as a person becaus the world is harsh on him, bo-ho. This I find very true for Harry Potter too which I read later on).
Some were of course "aimed" at beeing more humoristic (Pratchett of course, and I remember Hickman/Weis as having quite much of that to?) and I guess that if I was searching for something like that now I could still turn to them.
In others like Redwall and Empire Trilogy the milieus are so speciell I think the could be inspiering even as the storys isn't very great.
Left in my mind then as just good storys which I can long for is Katharine Kerr and Robin Hobb, but maybe this division is just someting I'v got into my mind due to when I read and what appealed especially to my taste rather than the actuall litterary quality.
For "non-fantasy-still-fictional-in-some-kind-of-medival-setting" I had Ronia the Robber's Daughter, The Brothers Lionheart and Mio, my Mio by Astrid Lindgren read to me as child, and (before the fantasy I think) I read some Robin Hood and Ivanhoe storys as well as The Long Ships/Red Orm. In the middle of my teens as I started to seek away from just consuming the same types of fantasystories over and over again I read a Beowolf translation on verse and Heimskringla by Snorri Sturluson.
All of these I remember as good or interesting because of their historical basis and can higly recomend.