Microsoft have dropped the subscription/gold requirement for Live on the PC
http://www.1up.com/do/newsStory?cId=3168931
--These features -- including multiplayer achievements, matchmaking, cross-platform play with the Xbox 360, GFW voice chat, and more -- previously required a GFW Live Gold account. The change is effective immediately and across all GFW titles, both past and future.
At last! Now I might finally get Gears of War