"A simple way of avoiding the above issue is to have a "personal" computer with personal accounts and activity, and a "work" computer, with work accounts and activity. Never use the work computer at home, and never use the home computer in the same place you use the work one. There's no way to confuse identities or traffic patterns."

The problem with this approach is that you need to never use the wrong computer for the wrong thing. You can help yourself somewhat by setting up different window colors / desktop backgrounds / etc, but what happens when you go visit your great aunt for thanksgiving and forget to pack both laptops? What happens when your work laptop breaks, and you desperately need to update the site to deal with some issue?

A more reliable approach would be to have one computer with two accounts (or if you like technically sophisticated approaches, use a mandatory ACL system), one for work one for personal things. Set up each account with noticeably different colors / themes, so that you are less likely to accidentally use the wrong account for the wrong thing. If you forget/damage your laptop, you have less of a temptation to use the wrong computer.

I am sure that Truecrypt fans will point out that hidden volumes work equally well, though the extra effort required is something of a stumbling block in my opinion (and I am not a big fan of hidden volumes to begin with).