Backing up wallet with pen and paper, destroying electronic copy, restoring from keyboard -- how? I have bitcoinQT with some coins on it.  I want to use the internet on a regular basis from this computer.  I do not trust the authors of internet applications and commercial operating systems.  I especially do not trust the manufacturers of printers.  I also do not trust that there will never come a day when burglars (or polite young men with a writ, same thing) with guns break into my home and take away all computing devices and storage media they can find. 

It is my intent to use a pen and paper to write down public key and address, and destroy all trace of bitcoin addresses currently holding value from all electronic media.  That which is not stored electronically - at all - is secure from all possible electronic snoops and all possible thieves of equipment, as well as from equipment malfunction.  That which does not exist, even in encrypted form on storage media, cannot even be shown to have ever existed.   

But having done so -- what exactly do I need to type, at keyboard, into a text file, to create something that bitcoinQT, when started with no known wallet on the machine (as though for the first time) knows how to import?  What exact format?  And how exactly do I tell bitcoinQT to import it?
The Satoshi bitcoin client has a dumpprivkey command available in the console, which outputs an encoded string of about 50-60 alphanumeric characters.  That should be pretty easy to write down, and it can be reimported with the importprivkey command.

But if you're really paranoid, why ever have your private key on a computer at all?  Flip a coin a bunch of times to generate some random bits, and then run the ECDSA keypair generation routine with a paper and pencil!  Hash the public key (you can use a computer for that part) to get your address, and transfer all your bitcoins to that address.  If you want to spend them someday, run ECDSA's signing algorithm by hand to make a raw transaction, key it in, and put it on the network.

Of course, stealing the piece of paper where you wrote down the key is probably a lot easier than decrypting an electronic copy.  It seems to me your trust is a little misplaced.