[Gabe]

CloudDrive

Cloud Drive: simple free online storage tool
Windows
CloudDrive is a free client software for Adobe Acrobat Online Storage Service, which offers 5GB free online storage for each account. So, when you use CloudDrive, all your files are stored in Adobe Acrobat Online Storage Service.


Dropbox
Dropbox - Home - Online backup, file sync and sharing made easy.
All platforms (windows, linux, mac)
The free Dropbox account comes with 2GB of space that you can use for as long as you like. Need more than 2GB of space? We offer Pro plans up to 100GB to meet all your sync and sharing needs.

Windows Live SkyDrive
Welcome to Windows Live
Windows
Let's get serious about free storage space. 2GB is fine for documents, but it's not enough for everything you've got. Maybe you can't get enough free space in the cloud for everything, but Microsoft comes close. Its SkyDrive online storage delivers 25GB—free. The only limit: You must keep to no more than 50MB per file.

If your thinking with a local hard drive or spare space...

I would give

GFI backup home edition a try. It's free and does a pretty good job.

Here are some instructions for it.

GFI Backup Home Edition is a Free Data Backup Utility for Windows - How-To Geek

 

[monkeywrangler71]

I use Dropbox and love it.

 

[starsapphire]

I use Dropbox too - its great for storing copies of my college work in case of computer failure.