Cloud storage is life saver and the future. I had been using a couple of different online file archive / backup services, such as Mozy, Skydrive, DropBox, etc. There are lots of comparsion between product X, Y, Z out there so I won't repeat. Below are just my personal top 2 preferences and sharings:
Firstly, I like DropBox very much because it save my life last month by restoring / undeleting some important business and working documents for me. It's small (2GB) and light, fast and easy to use. Just create a folder, drop something there and all set. It appear on my iPhone, laptop, etc instantly.
Secondly, I use Skydrive to store my personal files and the Cloud Storage Explorer (formerly called SDExplorer) free edition is also my companion. Skydrive is little bigger (5GB - specifically for Live Mesh) but the interface is slow and not so user-friendly though.
Anyway, Cloud Storage Explorer doesn't work tonight then I go to the Web interface immediately. I learn that the interface is changed, then I switch to the Skydrive Web interface anyway.(I was wondered why the interface change would affect the explorer tool itself, assuming the API call behind have no direct relationship with the Web interface at all). I also confirm that it is a known issue because it had been announced on the official Cloud Storage Explorer website yesterday. Similar to DropBox, Skydrive also provide a file sync tool called "Live Mesh", which synchroizes files across devices.
Finally, the storage "fee" of course another important factors, but I would leave this factor because I'm sure people is happy to pay more if they want more space, ensure the files are safe and freely accessible any time any where.
Figure 1 - Create a folder, drop files there and then files will be sync with DropBox / Skydrive automatically
Figure 2 - Skydrive synced storage Web interface