As far as PC cult classics go, System Shock 2 is the whip. Unfortunately, that "cult" bit is part of the problem--Ken Levine's lauded BioShock predecessor has been mired in licensing issues for years, preventing a re-release despite clamoring fans.
No longer. System Shock 2 will hit Good Old Games tomorrow, with a release on Steam set for some time in the future. Rock, Paper, Shotgun has more on the struggle to bring the groundbreaking 1999 horror/shooter/RPG title to widespread distribution, but you'll only need to lay down $10 to get your hands on it.
What better way to pass the time until BioShock Infinite releases on March 26? You could even be one of those so-and-so's who always says the original was better. Or in this case, the spiritual-predecessor-to-the-prequel was better.