Just by adding +identifier before the @ symbol on any Gmail or Google Apps email account, you can use an infinite number of email addresses that all drop into the same account.
e.g.
All of these messages will drop into first.last@gmail.com. You can apply filters via the identifier.
While I absolutely LOVE LastPass for my password management, I must admit that I’ve got a ton of accounts spread out over several domains, and it is quite a pain to manage. I wish I had known about this two years ago!
Thanks Jeff Douglas for the great tip!