Arcanum is, in a word, huge. I spent an entire month just trying to get started with this game; my OCD kicked in to full throttle going through endless combinations of race, alignment, and disposition just to explore all of the options provided by the initial dialogue tree. So much to do, to say, to see right from the very beginning. Eventually bringing you to the city of Tarrant. Never has there been a city in an RPG with so many different characters, so much politics, so many quests. The balance of tech against magic, the choices, the true fulfillment of not just playing another chosen hero, but truly playing a role and one that you craft.
This is easily in my Top 5 RPGs ever, and truly one of the greatest games of all time.