Here's a list of the best stuff that you already have but maybe didn't realize.
- Disk Cleanup - It's improved, built-in and much easier to find free space in Windows
- Reliability History - In the Windows 8 Start screen, type reliability, click Settings, and then select View Reliability History. You'll get a fantastic view into how your machine is running, what works and what doesn't. Often I'll find that it's a specific or driver that's causing my troubles, rather than Windows itself. This is a great unused tool for getting to the bottom of reliability issues.
- Display Calibration - Another app I once had to install, now built-in. Type calibrate from Start, and get all your monitors' colors correct and clear. Crucial for those who work on the web or in PhotoShop.
- Problem Steps Recorder - This gem was also in Windows 7. I often have my Mom use it to show me bugs or issues she runs into.
- Hyper-V Virtual Machines
- Windows 8 Pro includes Virtual Machines out of the box. Search for
Features and Add "Hyper-V" to get a complete hypervisor that can run
Ubuntu or older versions of Windows at near full-speed.
- NOTE: Your processor needs SLAT to use Hyper-V
- Task Scheduler - An oldie, to be sure, but one even I forget I have. If you have to do something often, scheduled it. From the Start screen type "Task."
- Memory Diagnostic - Concerned about bad RAM? Type "memory" as Windows now has a built-in diagnostic tool!
- Resource Monitor - Type "Resource" from Start and get deep info into what Windows is doing, even beyond what Task Manager tells you. I use this to find rogue services.
- File History - It's like Time Machine. I've got File History backing up my files hourly. More than once this has saved me when I needed a file off my desktop...that was deleted last month.
- Storage Spaces makes a giant drive out of a bunch drives. I actually copy my File History to a number of drives added into a Storage Pool with Storage Spaces. All built in.
- OblyTile - This quirky little app exists for one reason: to make prettier Tiles for your Windows 8 Start Screen to replace the ugly ones your regular desktop apps make. You can also pin Folders, commands like Shutdown, and generally make your Start Screen lovelier than it is now.