What can i say... Bioshock
System Shock 2 is the first game i remember playing, i mean really playing, with a feeling. I couldn't say why not Half-Life or HOMM or BG, i liked them all, but as time passed whenever i would think back System Shock 2 would bear the most powerfull memories.
So when i heard of a "spiritual successor" made by the man behind System Shock 2 and Thief i couldn't help to smile. I especially liked his interview, the dystopia motif, the fairly simple but powerfull vision of things, the seclusion, madness/sadness. If this is done well, and i think it will, it's bound to be an experience.
Unlike sequels where bored developers tend to move the game "to the next level", usually in a new, uncalled for direction i hope a "spiritual successor" will be able to recreate the atmosphere.