2 Gb in the cloud for free
Have you ever forgotten that USB-stick with your presentation or the important document at home?
Dropbox solves this if you have internet access.
Browse to http://www.getdropbox.com and register to get 2 Gb for free. More space can be purchased if needed. Clients exists for most operating systems.
The communication between your client and Dropbox is encrypted (SSL with AES-256 encryption). So unless you are breaking a company security policy or you do not have internet access there is no excuse to send a copy of the file to Dropbox, just in case.
Dropbox presents itself as a folder on your desktop (or wherever you choose to put it). You can also share folders with other Dropbox users. To add to this there is a basic revision system, so changes to or deletion of your files can be reverted.
Highly recommended! Read more about it: http://www.getdropbox.com