The new service pack 1 is out for Windows 7 and awaiting your download. This service pack includes all the updates to date with Windows 7 plus a few tweaks to the operating system. By the way it also includes multiple ways to detect pirated copies of Windows 7 so if your copy is from Uncle Bob you might not want to download it. Other than that it is a good download to update your computer.
It is very important to keep your computer updated. When a vulnerability is found to is "patched" by Microsoft and the "patch" is released as an update, they also correct any issues with the operating system. It is a pain sometimes to download all the patches but a necessary evil.