What was your first non-D&D fantasy RPG?
Palladium Fantasy. Great setting, mediocre rules.
Hard to pick one. I have outgrown WFRP, in the sense that it no longer appeals to me setting nor rules.
I am, howver, fond of several for different fantasy genres...
Arthurian: Pendragon, 4th edition.
Renaissance Fantasy with Tolkienian races: Arrowflight 1st edition. (dislike the 2e mechanics)
Dungeon Crawling: Tunnels and Trolls - 5th ed mechanics, Deluxe ed types (=classes).
Semi-dark Fantasy: The Arcanum (I've not gotten the recent 2e to table
Pony: My Little Pony: Tails of Equestria. Solid rules light game. Really well done.
Furry: Pugmire/Monarchies of Mau/Pirates of Pugmire.
OSR: Mazes and Minotaurs. If this had really been out in 1981, instead of D&D, I'd have had even more enjoyment. The author did a brilliant job. It runs well; I had a game run to 3rd level. Stopped due to work schedules.
Silly: Og: Unearthed
Space Fantasy: FFG Star Wars
Chanbarra: Feng Shui 2.
If it is a different answer, what is your favorite "fantasy heartbreaker" (usually defined as a game designed specifically to be a better game than D&D and usually failing)? Are you able to run that favorite game, or do you end up going back to D&D to get players (or whatever other reason)?
I've still got a soft spot for Palladium's world. It's the heartbreaker that succeeded.
The Arcanum had a great setting (antediluvean Atlantis, Lemuria, and Mu), and took the same mechanical bits as Palladium, but did it in a more sensible manner.
I've also a soft spot for Rolemaster.
There are several I want to get to table, but may never do so:
Paleomythic
Gubat Banwa
Savage Worlds
In Nomine (but only with the right group in private)
I've bought several games just for the reading value...
World of Og. (I got Og: Unearthed to table several times) If one is going to do Og, do Unearthed.
Dragon Warriors - got it to table. It's not horrible, but the adventures are NOT balanced well, and it's very swingy. Party voted to not continue.
Numenera. Numenera is an interesting read, but I'm not certain I'd want to actually run it. It's definitely more accurate to Dying Earth than was D&D... while still not quite being Dying Earth.
I'll note also my favorite modern "dungeon crawler" - the infiltration borderline RPG/boardgame Ninja Burger. Not the nasty PDQ system 2nd ed. The highly tactical 9th level games version. And its sibling, Kobolds Ate My Baby.