e.g. Easy Youtube Video Downloader

Also, let me add that my machine (1GHz) can hardly cope with any flash using firefox and the gnash-plugin (ubuntu). But! I can easily unplug a video (usually, e.g. youtube works) with the unplug extension and then play that same video with totem (not using any non-free codecs, w32 or whatever) without a glitch. So flash (especially once gnash gets better) doesn't suck that much but with the browser plugin it does.