It really depends on what you want to use the storage for.
I use Box.net, MiMedia, SkyDrive, Dropbox, Cubby.
25gb, 7gb, 25gb, 10gb, 5gb respectively.
Plus a few others that, I seldom use,
but in my bookmarks with registered account.
The preferred options are to have it workable through the web.
And with the optional desktop deal.
I found some desktop applications are good, others are not.
They either hog your memory or carry unwanted adware.
There is imageshack and photobucket too.
And Minus, which is very cool.
Just add .com to any of those names to bring up the page.