Can you say something about TrueCrypt compared to FileVault ( http://en.wikipedia.org/wiki/FileVault ) the encryption facility that is embedded in Mac OS X please?

see:
http://www.nytimes.com/2008/02/22/technology/22chip.html
for one of many ways your computer can be compromised.

Basically, almost nothing can stop a determined and resourceful attacker with physical access to your computer.

That said keeping your truecrypt volumes in an unmounted state may be a good safety precaution. another would be to use whole drive encryption and then using truecrypt volumes within that, which you keep unmounted.

Also, choose strong passwords. strong passwords that you can remember. but never store your password on your computer unencrypted, because your hard drive can be downloaded to someone elses hard drive and ALL strings in the drive can be added to a password cracking dictionary.

A trick i use is to take a password i have been using for a while, and then mutate it on paper, while keeping the way i pronounce it in my had. Say i used chose the word “macbookair” (I didnt, and you shouldnt because its now public, but this was a good password for a base because it takes three dictionary words and puts them togather for my password). Then what i might do is capitalize certain letters and change the o to 0: MacB00kAir, now i add some more shifts and it looks like MacB))kAir or maybe i move some things around and its now nACb))K02 (02 for air). This might seem diffucult, but once you have a strong password like this, there’s no need to change it often (some may disagree) and once its memorized and you use it every day for a week, its memorized.

Ok, there’s my 3 cents