Video DownloadHelper
I know this is a FireFox extension, but its free and it has the ability to identify all the media: video, audio and images available linked on a web page and download one or all in a couple clicks. It works with almost every site that contains media links (not just flv) and its got a list of popular sites (that you can filter to prevent adult content). It will convert to any of about 15 formats including galaxy pad, iPod, Zune, and of course mpeg, mp3, mp4, mov, wmv, and more. So, even though its limited to FireFox -- I think it deserves a mention just for the breadth of capability for a price that is FREE.