I have used Dropbox for some time and it is an excellent tool, not to mention FREE!
They also allow you to gain more memory space with referrals, meaning both the person giving the referral as well as the person signing up get additional space.
For every friend who joins Dropbox, we'll give you both 250 MB of bonus space (up to a limit of 3 GB)!
So I shall gladly share my referral link to anyone who wants to take advantage of this great FREE utility:
Sign up for Dropbox
Enjoy!