Yes. Linux
The benefits
Where to begin? Linux is secure. No more worries about spyware or viruses messing up your system. It's stable, so you don't have deal with blue screens, or freezing, or the systems running slower over time. Linux is also legendary for using hardware effeciently; often a computer that struggles with a resource-hogging OS will zip along great with Linux.
New system, same computer
So you think you need a whole new computer. "Wait, I just bought this computer 2 years ago" you say. Well, maybe you just need to add more RAM. "Except 2 years ago my RAM was enough to do the same things that are slow now" you say. You could switch to something different like a Mac. But what about putting something different inside your current computer? Like a brain transplant. Your same computer with a new way of thinking.
Your stuff
So enough with the geek-speak. O.S. shmo-S, what about my stuff? No problem, Linux can handle it. Your documents, music, photos and videos will still be at your fingertips. And the internet? Linux was raised by the internet. Broswing the web, managing your emails, or instant messaging with friends is a walk in the park.
Made to be easy
Ever had a hard time finding something you installed, poking through your menu trying to remember the name of the company who made it? With applications in simple categories that's not an issue. Adding supported hardware is as easy as plugging it in; no loading drivers from a CD or waiting to restart. Need more applications? You might be used to searching the internet and wondering if you can trust the sites you download from. On Linux just use the Software Center, which has thousands of applications from secure trused sources in one place, installable with a few clicks.