Is it possible to view all of my purchased DLC for a given game on Steam? I want to know which expansions I've already bought, and pulling up the game's DLC page lists all DLC without indicating which I have purchased, even when logged in. I don't want to go view each content's page to try and figure out if I have it or not, and I don't want to need to download the entire game to see what I have.
Yes, if you have the Steam client installed (with or without the actual game) you can find the game in your library, right click on it, then select "Properties". From there select the DLC tab to view your purchased DLC.
Alternatively, select the game in your library and click on "CD Key" under the links. This will list your game and all your owned DLC.