iTubeX Ultimate is a video downloader with the following features:
– Download YouTube Videos as a .flv or high-quality .mp4 file.
– Download .flv, .mp4, .mp3, .divx and .swf files from almost all other video / animation websites.
– Convert the downloaded files for use with mobile phones and more!
To convert some filetypes (including .flv), Perian has to be installed.
Perian is a free QuickTime Plug-in which adds support for more filetypes.