I use LastPass myself. The browser plugins and extensions are very
nice and work on Mac, Linux, and Windows. The more I use LastPass'
form fill features the more I don't want to be without it. Sometimes
it's really nice to be able to make a purchase online with just a
swipe of my finger on the finger print reader or by entering just your
LastPass master password (LastPass can utilize the fingerprint reader
on my Windows work laptop for authentication, don't know if this works
on other operating systems).

My understanding is encryption is done on the client side, so you're
only storing an encrypted blob on the LastPass servers. I'm also a
premium customer ($12 year) and I have a YubiKey attached to my
account as well as my wife's, though I've set my computers that are
encrypted and have reasonable timeouts for screen lock set to be
trusted and not require YubiKey after initial setup.

I also setup my wife with LastPass, and now we can securely share
passwords with each other on shared accounts.
-- 
Andrew S. Zbikowski | http://andy.zibnet.us
IT Outhouse Blog Thing | http://www.itouthouse.com