Mac: Dropbox's revision history is a great way to pull up older versions of files, but it's not exactly easy to use in the web app. Revisions for Dropbox is a Mac app that lives in your menu bar and makes browsing file versions a breeze.
With Revisions, you can browse file history by date, type and location. You can search for specific revisions to narrow down on your search and find the exact file version you're looking for.
You can then load up that older version of a file or restore revisions in bulk. The app's free, but an in-app purchase unlocks extra features, including the ability to see which user edited a file, advanced filtering, and more. That said, for most of us, the free version is plenty.