I think we all know Dropbox by now. This cloud-based storage service pioneered the personal IaaS cloud service. Unlike the other cloud systems, Dropbox doesn't need a web browser interface. It will run natively on almost any PC (including Linux) or device platform.
That makes Dropbox pretty darn handy, since you can treat it just like any other drive with your favourite file manager. For better or for worse, though, file storage is all DropBox offers.
On the other hand, sometimes that's all you need. It lets you easily get to your most important files no matter what PC, tablet, or smartphone you have in hand at any given moment, so it's quite popular.
Dropbox only comes with 2 GB of free storage, but since it's primarily for documents and not media, that may be all you need. If you want more, Dropbox charges $9.99 a month for 50 GB and $19.99 for 100 GB. That makes it one of the more expensive services out there.