Best Way to Protect Harddrive Data?

[pp2]

TrueCrypt imho is better that DriveCrypt, since it is open source, so you can compile it yourself to be sure there is no holes in protection and undocumented features. It is also free and have well-documented protection mechanism for better understanding what you can get using it. But it is lack pre-boot auth and some other nice features...
Anyway give it a try: hxxp://www.truecrypt.org