From security aspect, Secunia PSI is simple and easy to understand. It also offers automatic updates for some software such as Flash Player. I would consider using this on a modern computer for a novice Internet user.
FileHippo Update Checker provides update notification and directs the users to their website. It also offers beta software updates as a bonus. I would consider using this for any PC, who don't necessarily are interested in updating their software immediately.
Note, if you use Chrome or Internet Explorer on Windows 8.x, updates are done through their update channels (Google Update, Windows Update).
A lot of software now have their own built-in software updater, and even Portable software have this too.
Windows Store App update automatically through the Windows Store Update channel, but as long as it's not a desktop app.
- Windows Update
- Windows Store
- Built-in updaters
Voted, Other.