March Madness Non-D&D Blog Challenge: Day 7: What fantasy RPG other than D&D have you enjoyed most?

What fantasy RPG other than D&D have you enjoyed most? Why?

Well, there are two ways to approach this question.  Which set of rules have I enjoyed most, as rules, and which games did I have the most fun with even if the fun had nothing to do with the rules per se.  I mostly GM, so knowing and using the rules becomes a bit part of play.

I think I really have to go with Chivalry & Sorcery, both as player and GM.  This was the game which introduced me to the hobby.  Looking at the books now I see how clunky it really is and how some classes get all the love.  But I still remember the sense of wonder as my character stared up at two giant skeletons with flaming skulls guarding the gate to the city.  Pure magic.  Then I began my own game and the combination of intellectual challenge and creative freedom was electric.  Yes, I would have to say Chivalry & Sorcery.