The reality is, nobody is going to physically attack your laptop (just don't bring your work machine to Black Hat). But there is an unacceptably high probability that your laptop will get stolen; for instance, you will often leave it in your car, where anyone with a cinderblock can get it in under a minute.

TrueCrypt is about the guy with the cinderblock, not about stopping Joanna Rutkowska from installing a keylogger.