I'm seeing a lot of binary-code submissions in base64 encoding. Wouldn't Hex be better, from a presentation point of view? I can read hex, I can't read base64.
Personally I like hexdump format, as used in one of my answers. That way, any readable stuff is actually, well, readable. :-)
I think both forms have their usefulness.
If the vast majority of the program consists of random binary data, a hex representation isn't going to be very useful. A base64 encoding, on the other hand, gives users the ability to test your program directly, without having to perform any manual conversion - especially if you provide a wrapper which generates the program, such as provided for this answer or this answer.
For shorter answers, and those with a minimal amount of non-ascii characters, I do agree that a hex representation will be more useful.