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