brotherhood_of_LAN - 4:30 pm on May 24, 2011 (gmt 0)
Indeed, it's the part of computer security that's often forgotten, I remember looking at case studies of it in education.
Physically securing the computer is really not too different to securing the room that the computer is in.
A safe. Anything that can be 'taken away' i.e. not bolted down can eventually be broken into.
And although encrypting your data doesn't fall into the category of 'physical security', it is another level of security that prevents your data from being stolen.
Your hard drive is essentially what you need to keep safe (again, if it's the data and not the hardware you care about)