Priced at $49.99, the Game of the Year Edition bundles Bethesda's post-apocalyptic RPG with the five downloadable expansions--Operation: Anchorage, The Pitt, Broken Steel, Point Lookout, Mothership Zeta--that arrived post-release at $10 a piece.
At present, the all-inclusive Game of the Year Edition marks the only way to purchase the expansions through Steam, as the individual add-ons for the regular edition can only be acquired through the Games for Windows Live Marketplace.
I've been hoping this would hit Steam. I have GOTY for my PS3, but maybe in a year or two I will pick this up for PC because of the mods. I imagine there will be some really neat stuff coming out in the next year. I hope!