We put five free online storage services, which let you upload your files to a 'virtual hard drive' and access them from your other devices, to the test to find out just which is the best one for you.
Dropbox, OpenDrive and ZumoDrive represent best the concept of cloud-based file storage, syncing and sharing: Their desktop programs embed a virtual drive within the file structure of your operating system. Their premise is to work as invisibly as possible by functioning like a normal drive.
OpenDrive gives you the most online space for free - but I occasionally encountered problems when trying to sync/upload files that were a couple of megabytes in size through its Java-based desktop client.
Between Dropbox and ZumoDrive, it's pretty much a draw. If you have colleagues or friends who already use Dropbox, that could give it the edge. Still, you may want to check out ZumoDrive and open a free account, since its desktop client includes built-in features that make it convenient and easy to share your media among your various devices.
See also: The 20 best online collaboration tools