I'm pretty dependent on Google tools for everything outside of my day job: mail, reader, blogger, analytics, documents, notepad, and calendar. I've seen things screech to a halt around church when they have an email outage.
This post on Google Operating System has some really good tips for using a second Google account as a backup in case something happened to your primary account. In most cases it's as easy as just adding the second account as another user on your blog or Google docs. I need to do this.