Thanks for your answers so far.
Well, I carry my notebook around with me. My wallet is on an external HDD that I do not carry around with me. (Save so far.) What I worry about is that the HDD could be stolen from my home, connected to another system and abused.
Would an HDD encryption protect it? What if the thief takes the notebook, cracks the Windows password and uses it to gain access to the encrypted HDD.
Again: what kind of protection would you recommend?