Here is why you don't want to encrypt everything on your laptop:
Redundancy:
Encrypting files who's contents are known, the operating system, for instance opens your encryption method to known plain-text attacks. This is a big reason WEP is so easy to break. Known attacks for WEP exploit the redundancy in TCI/IP packets. Practical Cryptography by Bruce Schneier has a fun read about WEP.
Corruption:
Encryption makes files susceptible to corruption. A bit wrong in plain-text ruins a character of a text file. A wrong bit in an encrypted file ruins not only it's self, but propagates errors elsewhere.
Slashdot Mirror
Here is why you don't want to encrypt everything on your laptop:
Redundancy:
Encrypting files who's contents are known, the operating system, for instance opens your encryption method to known plain-text attacks. This is a big reason WEP is so easy to break. Known attacks for WEP exploit the redundancy in TCI/IP packets. Practical Cryptography by Bruce Schneier has a fun read about WEP.
Corruption:
Encryption makes files susceptible to corruption. A bit wrong in plain-text ruins a character of a text file. A wrong bit in an encrypted file ruins not only it's self, but propagates errors elsewhere.