My favourite RPG tied with Chrono Trigger. Before its release I was getting tired of JRPGs with stories so convoluted that you just tag along just to watch the next beautiful cutscene with very pretty graphics to mask its shortcomings—then came Xenoblade Chronicles...
Everything just clicked: a grandiose epic but coherent and easy to follow story; a charismatic cast that you are welcome to follow because of their camaraderie and support towards each other; incredible voice acting; very quotable dialogue; INCREDIBLE battle music, field music, and cutscene music; unique turn-based battle gameplay; vast open exploration of the environment in this artistic and imaginative world; and the philosophical points the story puts forward that really made me think.
I cannot praise this game enough. It's a masterpiece!