Well here's something that might be interesting.
Strife, one of the last first-person shooters to use id's Doom engine and earliest FPS/RPG hybrids has finally escaped abandonware status. Night Dive Studios, the same folks responsible for resurrecting System Shock 2 on GOG.com and Steam, has brought this overlooked gem back on Steam as
Strife: Veteran Edition. What's new about this version, you might ask? Native compatibility across Windows, Mac, and Linux, higher resolutions and widescreen support, OpenGL rendering, new lightning and bloom effects, rebindable keys, and some other Steam-related bells and whistles. This version also brings back the original game's lost features, such as objective markers for your automap and the "Capture the Chalice" multi-player. It can be yours for $9.99, but between now and December 19, it's on sale for 25% off.
As a little tidbit of trivia, Samuel "Kaiser" Villarreal, the same guy who created custom levels for a bunch of FPS titles (Quake, F.E.A.R., Unreal Tornament, Serious Sam, etc.) and working on the Doom 64 EX port (and it's a damn fine one if I say so myself), has co-developed this enhanced version of Strife.
-EDIT-System Shock 2
90% OFF on Steam for the next 40-something hours!!
-EDIT 2-SYSTEM SHOCK 2 GET!