Best Free Encryption software

Note:
proper encryption software *must not be secret at all* otherwise you have security by obscurity and this has so far allways proved to be not very useful.

If a software is able to encrypt AES256 so what more you need? OK, it should delete all 'working files' after work done not only from all temp positions but also from all buffers like hard drive buffer etc, but then?
Algos like AES, 3DES, CAST5, Blowfish, Twofish, IDEA etc. are all well documented and reviewed by thousands of scientists, so we can assume them to be safe as long as no one discovers some new ways of of attacks against such algos.
At present, estimation of brute force attack against such algos, might with present day big computers take more then 10e10 years as someone did calculate apparently and this is difficult to use, since I was told that the sun will go after abt 10e7 years suppernova...

You can use zip or similar and use the build in AES256 or toucan or what ever.
Free version of pgp might do it more comfortable, similar gpg with some of the graphical front ends around.

In general, open source and openly known algorithms are considered better, since no special hidden mistakes or even 'backdoodrs' are posibly included, since every programmer can review such software worldwide thus the probability of some problems in it are rather small.