... miss the point of full disk encryption, which is to avoid having to notify the news media when a drive that may or may not contain social security numbers is stolen out of the back of a car.
If you really want to stop these sorts of attacks, the good old "boot disk" technique is the beginning and the end. Using a TPM for this is overkill, and arguably less secure.
Many laptops now have SD card slots that could be used for inexpensive boot disks. A USB dongle would also work. Take the boot disk (that has the key on it) with you when you leave your computer. Encrypt everything else.
Even that doesn't stop the $5 wrench attack (well, unless you anticipate it and flush the SD card down the toilet). The actual best thing you can do is just not keep sensitive data on your laptop.
Maybe I'm dense, but what is the $5 wrench attack? Attacking you personally with a wrench until you agree to show me the sensitive data on your machine?
A side note: two-factor authentication (smartcards, etc) -- which minimizes Evil Maid exposure -- is unsupported on the OSX version of PGP Whole Disk Encryption.
Schneier's gloss doesn't add much.