With Gnash, for example, you just have to configure it so that it saves the
stream in some accessible place, run the stream completely once (even if you
start the video again, or if it stops playing to be loaded, what matters is
the stream, which is loaded until it's end), and then you have it, saved
where you configured Gnash to do so. It won't download subtitles.
As you might guess, this method only works if you can actually see the
stream, otherwise you'll just save a black video. Also, don't forget to
revert your configuration once done downloading, otherwise, Gnash will surely
keep saving streams every time you use it.
Best regards, ADFENO.
Have a nice day.
Addendum: Oh my... I just hope I haven't broke the forum rules or guidelines.
Anyway, I only download videos for my parents, mainly because I don't need to
download videos for myself using Gnash, just because I hate YouTube, Google,
Yahoo, and others... I have the Internet Archive, Vo.do, Clean Bits and other
sites for that matter.