Encryption and security is actually a topic i have NSA training...

Encryption and security is actually a topic i have NSA training and certification on.

The encryption standards are public, the main ones the NSA use and recommend for all classified documentation is SHA for hasing and AES for encryption, the ones used with your linux install are secure and will use the same types or other standards which are as secure, you should not be able to get around them without knowing the password. Oviously dont use a simple password and the longer the better as it will create a more unique hash that cant be hit with a rainbow table.

BIOS encryption should also be secure as well, as it will use the same open standards, but using both would be silly as you are then encrypting twice which will slow things down.

If you use a sensible password your data should not be able to be attacked with physical access.. Your password is turned into a hash which is not reversable, you can only attack it with brute force or rainbow tables, so long passwords that are not stupid will fail both these attempts.. Without knowing the hash you cant decrypt the encryption key which is encrypted with the hash, which means you cant recover the data.