There are plenty of nice games to download for free -- e.g. Team Fortress 2, AirMech, Star Wars: The Old Republic, DC Universe Online, ... (Not trying to advertise here.) So if you're interested in playing at least one of the before mentioned titles... Then sure, why not! :)
You can get my Steam tag on my profile.
PS: @SaifurRahman, Steam is a PC cloud gaming platform, as if you can take your entire gaming library with you. It's very useful if you own a lot of games, although you won't get that warm feeling inside anymore of opening a box. :(
(Except if you buy a Steampowered game, which run on Steam, box or not.)