Fantastic thread, but it needs updating badly. After selling thousands of tubes over the years, I also want to note my objection to the following statement:
having military or original boxes - these vastly increase value. If you are taking a box from another source and packing your tube in it, it is unethical to not mention so.
The brand box is perhaps important from the collectability feature it has on its own. However, the branding on the box is even less important than the branding on the tube, which itself is not very important. Tubes were often sub-contracted and mixed among mfrs on a regular basis. The box that a tube comes in is in no way an authoritative indication of the tube's manufacturer. If a tube dealer is really lucky, he is able to acquire tubes in their original "egg crates" as they came from the factory - 100 tubes in a single box, separated by cardboard liners. In such a case, the individual box one of those tubes is placed in is simply to contain the tube, nothing more.
There are definitive ways to recognize a tube's mfr - the etched dot pattern used by GE and the elongated octagon symbol with tube type printed inside for RCA tubes. For instance, you will find many tubes that come in RCA boxes, painted "RCA" on the tubes, but have the GE etched dots underneath or vice-versa. Similarly, you may have DuMont tubes that have RCA octagon designations.
There were also entire firms who did nothing but buy, rebrand, and stuff tubes in their own boxes - ICC, International, National Electronics, Richardson, etc. There is nothing wrong with these tubes and most are completely original tubes from GE, RCA, Tung Sol, Sylvania, etc.
Beyond that, you have to almost depend on the tube seller and his knowledge to know the true manufacturer of a tube. The box means almost nothing.