The BOB CD's are updated quarterly, unless it's something super-freaking important, as was the case when we got a new homeoners policy document when my previous insurance comapany went under.
The most important thing I have on the computer, though, is the "mirror" drive. Basically, we're talking about an updated data set continually availible in two places. this is just good dpractice for anyone who uses a computer, not an "equipped" issue.
The funny thing is that we've pretty much abandoned desktop computers here at my office (which is also my home) - my wife and I have have matching iBooks, and they are quite small and easy to carry, so for a grab and go situation, the laptops are up there with food and water.