WillFly, I've discovered it's not YouTube that makes me keep my original files, unchanged, on my hard drive, it's iTunes. Anything I've uploaded to YT stays there.

Oh, and I find YouTube very handy for "storing" videos even if I don't particularly want a lot of people seeing them. First, you can make a video private. But if you want to make it available to selected people who don't have YT accounts, just give the video a really cryptic name (e.g "fghjkeo200s") - and make sure the original file had a cryptic name like that too -- and don't list any key words. That way, your video will never come up when people use the YT search engine.   But you can send the link to whomever you like.

Nick, unfortunately, SUPER isn't supported by Mac.

richd, my videos have all been made directly by using the built-in camera and mic on my MacBook and using iMovie to edit them.
iMovie does, indeed, offer a lot of options for saving my videos.
That's my problem: I don't know which are the best options.
Usually I save them as .mov (QuickTime) or mp4.   If I put them on iTunes they usually end up as m4v.

But I would like to be able to make some promo DVDs (up to about 4.3 GB per DVD) that my clients and prospective clients can play on their TVs, not just on their computers.
I was just wondering if either the .mov or mp4 or m4v format would be playable on most people's TVs (with a DVD player).

Genie