[Zeitgeist]

...on another note, has anyone here been able to get XCOM Apocalypse working on Vista? I want to buy/play it, but I get the impression that there are a lot of problems getting it to run in Vista.

from wikipedia (so take with grain of salt)

On September, 5th 2008 the XCOM series, including XCOM Apocalypse, became once again available for sale on Valve's Steam platform. The game uses a specially configured version of DOSBox[citation needed], an x86 emulator that allows the game to run on operating systems supported by Steam, such as Windows XP or Windows Vista.

although i would have a hard time imagining you couldnt get a refund from steam if the game didnt run on your platform