I'm studying abroad for this semester, and I've noticed that all my Steam save games are gone. I don't use Steam very much, only for a small set of games like Torchlight, so I'm not well-versed on how to analyze the issue and potentially retrieve the saved games. Any ideas?
Games with Steam Cloud support may save games to Steam servers. You can see if a game has Steam Cloud support by checking if it has the Cloud icon beside it in Steam's Library List View. Unfortunately, even if a game has Steam Cloud support, that game may not save games via Steam Cloud and might only store things like keybindings or other settings. It also may not save all of your save games to Steam Cloud.
Even with Steam Cloud support, if you are using multiple computers it can sometimes take some time for all of your Steam Cloud settings and save games to synchronize with the server. Also, the save game support with Steam Cloud can be added as a late feature to a game after you've made a save, and that old save might never sync. I believe that if you are set in Offline mode, your games/settings won't sync until you go back to an online status in Steam.
Steam's Cloud icons on the Library List View will also sometimes inform you when there were problems syncing.
Torchlight, as an example, has provided Steam Cloud support only recently, and the support for full save games on Steam Cloud is even more recent. If your save games were created before the version with Steam Cloud save game support, those save games may not sync.
If you think that you are having Steam Cloud issues, your best bet may be to inquire with Steam's Support Forum.
Games that don't support Steam Cloud, or don't support saving games to Steam Cloud, will save games in "all the usual places", which means that it often varies from game to game, but is commonly in a folder under your