Not nearly enough people seem to know about this game, which I find strange, considering it's from the same people who made Fallout 1 & 2. Besides, as someone who doesn't play RPGs, it takes a lot for me to like one, and Arcanum does it's job in bringing everything to the table:
Imagine if the world of Dungeons & Dragons suddenly underwent an Industrial Revolution. How would the world of magic and technology intermingle?
The thing I like about it the most is the storyline and how what you do affects the ending and the world of Arcanum in dozens of ways. The game starts out with a plot which seems like LotR: The player receives a ring from a dying gnome after a zeppelin crash, and must return it to it's owner - who the gnome refers to as "the boy". But the game quickly dovetails into something entirely different: because the player is seen as the second coming of an important religious figure, Nasrudin, he/she becomes entangled in the struggle to stop an evil elf, Arronax, from returning. Along the way, the story deals with such philosphical issues as fate, how religion can be misintrepeted over centuries through things such as mistranslation and human misinterpretation, and how the way we view the world is shaped by our experiences.
The character selection allows the player to follow countless paths, and the nonlinear organization of the game allow you to roam and do quests at your leisure. There are several races to pick from, as well as character backgrounds, and gender. You can choose to be a mage following any of 16 different types of magic, a technologist following any of 12 types of science, or a pure melee fighter, a thief, or a hybrid of any - but a mage can not use technology and vica versa. Personally, I usually pick a mage, because nothing beats studying the force discipline and deatomizing your enemies near the endgame. Also, I highly recommend mastering the skill of persuasion, as it allows you to reach all of the best endings for each city and race, and gets into the more in-depth storyline. Besides, it's just cool to convince your foes into doing what you want them to do.
With the high replay value of any game, this is truly one of my favorite games ever. Unfortunately, when it came out, it had a few bugs, and some speed issues. Six years later, speed is no issue when running it, and the official patch and some player-made dialog mods fix the remaining bugs. Also, the game has one of the best soundtracks around. It truly makes you feel like you're in the 19th century with a great, classical feel. Play this game!
Links:
http://www.terra-arcanum.com/ - The best fansite around
http://www.terra-arcanum.com/sierra/ - The former official site, now hosted by Terra-Arcanum
http://www.terra-arcanum.com/sierra/media/media-soundtrack.html - Where you can download the soundtrack
http://www.benhouge.com/ - Homepage of the composer of the soundtrack
http://www.terra-arcanum.com/phpBB/dload.php - All the best patches and mods
http://en.wikipedia.org/wiki/Arcanum:_Of_Steamworks_and_Magick_Obscura - The wikipedia, which does the game more justice than I can.
