" 'it must be held in a file somewhere on the PC' theory doesn't work if ..."

well, not exactly...you have to stop and think just what a 'buffer' is. If I understand it correctly, all 'buffer' means is a cache or a temporary download folder. If you have an older computer with limited storage space, these large music & video files will be hard to manage no matter what, but if you have newer(last 3-4 years?) machine, and broadband, you should be able to deal with 'almost' anything. It is just a matter of KNOWING the default stroage location, and whether it is temporary (is emptied when you close your browser) or not.

As to flash (.flv)...There are BOTH converters and programs that will play them....look here, for instance......(I think I have 2-3 others that will play .flv without converting)...and this program will download from YouTube to a directory you designate.

You must assume that some clever folks will figure out the inner workings of these formats and make it possible to use them without being at the mercy of the a******s who try to control you.

The major thing to know is ***WHERE*** on your computer these downloads get stored, and how they are named....then you can go there and move & rename them!

It is really, really important to have a file manager that allows you easy viewing of the files you have. Try Free Commander.... there are several other good ones, but this one is easy, and make moving files quite easy.