One of my favourite computer roleplaying games is Fallout 2. Set in an alternate universe in which atomic war erupted in the 1950s, the player takes on the role of a survivor struggling to survive in the resulting wastelands. (The first Fallout has a similar theme, but I've never played that one.) More than a simple shoot-em-up, the game presented the player with moral choices all along the way, with supporting characters you could love or loathe, fascinating career options, challenging puzzles, and a real sense of poignancy. This was a fallen world, one that may have turned out better than our own if not for the nuclear holocaust. Music by the Ink Spots and incredible retro design added incredible depth and versimilitude to the game's atmosphere. It was a great place for a twentysomething bachelor with a love of SF and its post-apocalyptic subgenre to while away the hours.
Even though it's over a year away, I'm eagerly anticipating Fallout 3. From the looks of the official website, the developers are trying to keep the look and feel of the original games. I hope they succeed.