Windows: In addition to a controversial UI, Windows 8 brought some new improvements, including a cleaner, more usable task manager. If you don't want to upgrade, you can get the sweet new look with DBC Task Manager.
The app is portable and doesn't overwrite the existing task manager, so you can try it out without changing anything important. The new style sorts your running programs by active apps and background processes, and allows you to drill down into each app and take a look at which tabs are hogging up the most memory or CPU usage. The UI on the performance monitor has also been cleaned up.
The developer states that DBC Task Manager is a work in progress, so obviously use caution. Be sure to download the correct version for your machine (32-bit or 64-bit) from the source link below.