Talislanta. It was the first roleplaying game I ever saw, and I bought it's book of critters just because I loved the art. I have never had a chance to legitimately play it, with all my efforts being adaptations of the setting to the D&D rules, or with players who were just gaming for a lark (like my Uncle, who was convinced he could do pretty much anything in character).
It's a vivid setting with tons of possibilities in every line of description. The magic system is so cool I basically ripped it off for Elements of Magic, and theirs is more elegant because the system is less rules-heavy.
Oh, and I want to be able to play a bird man, or a cat man, or a man with two brains without seeming weird.
Actually, I'd probably end up playing a faux-human spellcaster, but it'd be fun regardless.