For holiday gift I was thinking of making USB/microSDs full of TV/movies. The intended recipients are not tech savvy types. They would be using windows computers, normal TVs etc.

What kind of file formats/encodings would be good to package the files in? What is safe and universally usable? And which ones are to be avoided? I'd like to guarentee they'll play without any fooling around with drivers or software.

And I want them to be as small as possible so that I can fit more stuff.