Such a breathtaking game that still has the best story ever told in gaming. With the inevitable arival of Torment: Tides of Numenera still being a long way to go, i couldn't help replay Planescape: Torment a couple of years after my first playthrough and it all came back to me.
The writting (dialogue, story, characters, setting descriptions, etc.) is out of this world and creates such a unique, interesting theme, setting and incredibly memorable characters. Every single piece of dialogue is excellent and worth experiencing the wealth of side quests for. The music is excellent and complements the theme of the game perfectly, and the voice acting (yep, there is a wealth of voice acting for the main characters) is excellent.
The graphics are beautiful in HD resolution, like a painting in motion.
If there's one game you need to play in your life, it's this one right here. There is no modern equivalent, it's completely unique and its quality has no equal. And here's a tip i've mentioned a number of times that succesfully helped people enjoy the game -.
Wen you start a new game, pour most of your points into Intelligence, Wisdom and Charisma, and put the difficulty to the easiest setting (it only affects the combat, and 9 times out of 10 you can avoid it).
The steady pace of the plot by doing problem solving (both environmental and through dialogue) through which you'll unravel countless memorable twists and the nature of The Nameless One and your companions, not to mention the answer to its thematical question - What can change the nature of a man? - will keep you more than occupied.
Complemented by the the brilliant music and the fantastic, beautiful settings all of which will keep you glued on the screen until completion.