The same four! ha ha ha.
Actually, offline media like paper wallets are considered the safest. Generate a random key by throwing a dodecahedron 76 times or flip a coin 256 times. That should give you a 256-bit key. Then enter this on the PS/2 keyboard of an offline computer in order to compute the bitcoin address. Print out both. Send your bitcoin to that address.
Printing out private key is not a good idea, a printer stores the cache of what it printed out, so anytone who hacks the printer can know what was printed out.
Work out the address by hand. :)