Hi all, As standalone video format I see no reason to use .flv. People, especially those on Windows, usually do NOT know how to play it or what it is, unless they happen to know VLC or Mplayer, which are Opensource and work on Linux etc. just as well and could also play back Ogg Theora.
So for standalone video I'd recommend to use MPEG-4 which in my experience is equally well or even better supported (for example, Windows Media Player should know what it is?). Also it offers better image quality at the same file size.
This is different if you want to have very easy playback in the web browser - which currently so not done, and would require an actual Flash player such as Flowplayer to provide playback controls etc. Then indeed Flash is one of the easiest and most compatible choices.
However I'd consider to just upload the video to Youtube, and maybe even use youtube embedding. There are some benefits here. On one hand, many people who dislike Flash (like myself) might even have scripts installed to access Youtube without Flash (Greasemonkey rocks!), might have scripts to download the video and play it back in a real video player (e.g. the youtube-dl package in Debian or the various Bookmarklets and Greasemonkey scripts).
But the biggest benefit is that the video might be occasionally discovered by people looking around youtube, so if you add a good description and keywords, we might gain some new Enigma users via Youtube, even if the Video isn't used on the enigma homepage itself. So upload it anyway. :-)