I'm a little security paranoid, there are a lot of times that
my terminal is available to prying eyes and listless fingers.
As a security minded individual, I would like to make sure to
lock down my Ubuntu (11.04b3) install in one of the best ways
I can think of, and require a dongle to access my box. Is this
something any of you other security minded people have done?

What are other great ways to lock my terminal? I would like to
make sure that not only the "average" user, but also the ABOVE
average user will not be able to penetrate my system without a
key. Let me know what you think, and other measures I can take.