Aidyn Chronicles: The First Mage. One of the best RPGs of it's generation and definitely the best on the 64. This game, honestly, had more potential than it showed. The Company ran out of (I assume) money so many aspects of the game were cut, others left in but not used (such as an intriguing item you receive that ends up doing nothing). Worst of all, there were a number of plot threads that kind of dead end.
The story, however, was one of the best I've seen. It's not the typical "Save the world from Hell" story (at least not until the last 30 mins of gameplay where someone apparently decided to shoehorn a standard cliche into the ending, when the game could have just ended at a previous point and been much better). The looming threat isn't some sort of demonic invasion, your quest is actually just to heal yourself of some sort of magical poison... Or is it?
Spoiler alert: It turns out you have to cure yourself before a magical ailment makes you go crazy.
There were tons of other things I liked about the game, from the characters, to the leveling system, combat, most of all Magic. The magic system was easily the most balanced and still fun that I've come across.
I'd love to have seen a sequel that could live up to the original's potential, or even a remake. Sadly the developer went belly under shortly after release. :'(