That tool backs up its (encrypted) password db to my Dropbox folder. It also backs up to an iPhone app. So I think the chances of losing all my passwords are pretty slim. And, now, I don't care whether one site loses my password, since all my passwords are unique.
Also, my dropbox is set up on my mac mini too.
In order to lose my passwords, I need to lose, at the same time:
1) my mac mini
2) my macbook pro
3) my iphone
Even then I would be able to recover things somehow, because my email goes through a third-party gateway, and I know the guy who runs it, so if I really do lose everything, I can contact him and ask him to reset my password on that gateway, and then log in to my email via that gateway.
I think the chances of losing my passwords are fairly slim.
For important passwords that I might forget, I apply another easily rememberable transformation, and write them down.
Throw-away password: "ex@mpl3"
Email password: "ex@mpl3p@55"
Finance password: "ex@mpl3p@55w0rd!"