More delicious recommendations from the selectbutton community!
The IBM-compatible personal computer has a long and storied history as a piece of gaming hardware. It is the bastion of North American game design, and its games often reflect a less arcadey, more patient, approach. The big PC divide is between MS-DOS, and MS-Windows (though this, of course, has various versions, and various compatibility issues steaming from that), though the rapid pace at which hardware is updated will cause problems for those wanting to play the newest releases.
Steam has become an incredibly popular way to purchase (digital copies of) Windows-compatible software, often at exceptional prices. Good Old Games (GOG) has been releasing updated, digital, versions of DOS games compatible with modern systems, while emulators such as DOSBox, and ScummVM allow people to run their older copies of games.