Among the most useful features is the ability to generate pop-up warnings on your screen to notify you of new entries in the log. You can also have these sent to you (or to anyone else) via email, which makes for a very handy way to keep track of friends' and family PCs to ensure that they're working properly. To avoid receiving too many popups and emails, you can filter on specific event types and set time intervals too.
If you're a techie and you want to ensure that your PC is always running at its peak, check out Event Log Inspector. It's only a 3 MB download, runs on Windows XP and above, and is available in both 32- and 64-bit varieties.
A Handy Windows Troubleshooting Tool that's Free For Non-Commercial Use Gizmo's Freeware