Any decent-sized business with half-a-clue about staying in business will create, manage and maintain some sort of Disaster Recovery or Business Continuity Plan. 

For independant publishers and small shops, there's no reason you shouldn't think about some safeguards for protecting your operations, assets and website.

Here's a list of things I do:

Data Loss

• Ensure Databases are incrementally backed up to a separate server (or subsequently pulled off the server)
• Ensure static files are incrementally backed up (as above)
• Ensure ALL source code / graphics files / content is backed up or placed in Source Control regularly

Service Providers

• Ensure login details, server addresses, FTP addresses, etc are kept in one secure document or File Locker
• Keep Contact Details / URL's for Customer Support contacts in one place - you may need to coordinate across multiple providers for hosting, etc

Critical Dates

• Place Calendar reminders in your diary for Domain Name renewals, Hosting Contract Expiry Dates, etc

Site Rebuilds

• Could you rebuild your site on a new server quickly? If not, document all those tricky steps to set up Databases, Web Servers, Security Accounts, Firewalls, etc

Got any more for the list?