Over the last few months I have transferred most of the my data and tools (email, documents and applications) online. It was not a conscious decision I took one day, in fact I remember resisting it a bit, but in the end common sense prevailed and I figured out that I am prepared to trust third parties with my stuff, so that I can get ease of access and use.
I have not looked back once since. I just took a few precautions: just to name a couple, my Gmail account automatically backs up with Zoho, and I chose to use a paying service (JungleDisk interfacing Amazon Simple Storage) to back up documents and photos once a week.
I have just come across one of the articles that originally sparked my curiosity in putting data out there: How To Live the Cloud Life, by Paul Stamatiou. It is a treasure chest full of tips and links to applications and services that will make it easy for you too to adopt this lifestyle.