Two simple programs to get most of your data safe and accessible from anywhere. Living life in the clouds is something that I've been doing more and more. Its convenient, reliable, and safe. Here are two programs that I recommend for day to day use.

Dropbox

URL: http://www.getdropbox.com
Description:
Dropbox links your computer with your account online. Both in Windows and Mac Dropbox is a simple folder. You put content in the Dropbox folder it stores locally on your computer and syncs with its online counterpart.
Convenience:
Not only can you sync and store your own data, you can share folders with other people and/or make folders and files public. No need to e-mail massive files anymore. For collaboration and work purposes, just drop files back and forth with others. iPhone has some capability with Dropbox and other mobile solutions are in the works.
Reliability:
Because Dropbox isn't online only, you have the convenience of local storage, but it is also backed up online. When something is deleted with in the Dropbox folder, it is deleted, however you can restore its online counterpart, which would restore your local file as well.
Safety:
How safe are your files? All syncing is done over SSL and all data is encrypted with AES-256 before being stored on their backend. I'd say its pretty secure.
Overall:
I use Dropbox every day for work purposes and to back up some of my smaller client files. I've never had a problem with it since I've been using it, and the features are only getting better.
As of right now, you are limited to a 2Gb account and can only link one account with one computer at a time. You can have separate accounts on separate computers and share folders between them to get your storage increased a little bit.

More information over at http://www.getdropbox.com/faq

I was initially going to post about how I use Google Docs, but in researching a bit I came across several articles including this one: Privacy issue: Google Docs seems to not delete but only hide documents when the trash is emptied. They all were pointing at security flaws and bad practices on Google's part. I took all my content off of Google Docs and looked for better services.
After much research and some testing, I came to like this website/program for a productivity suite in the clouds.

Zoho

URL: http://www.zoho.com
Description:
Zoho is an web based productivity suite including these applications: Mail, Calendar, Documents, Desktop, Writer, Sheet, Show, Meeting, Wiki, Tasks, Notes, Links, Contacts, and Notebook.
Convenience:
Having most or all of your documents online to access and edit anywhere is a convenience I would have liked to have had a long time ago. Using Google Gears you can sync your documents as an extra backup to multiple computers.
Reliability:
All of your documents are backed up on your computer as well as online. If something happens you can always recover. You can edit and access your documents from anywhere, including web able phones.
Safety:
Zoho has options to always connect to a secure server, only allow specific ip address to connect to your content, and you are able to see the sessions that have accessed your content.
Overall: I'm glad I decided to write this post because it forced me really look into Google Docs. Which in turn gave me a wonderful alternative that is leaps and bounds beyond Google.

These two sites/programs are a good beginning to living in the clouds. Backing up your entire computer or data collections is not what this post was intended for, that will be in a later post.
Check back for updates on new or better solutions.