Great Downloader easy to use can convert into multiple file formats. Fast and impressive
ClipConverter.cc - ClipConverter.
Video DownloadHelper - Browser extension to download videos from the Web
VidToMP3.com - VidToMP3.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
OnlineVideoConverter.com - OnlineVideoConverter.
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.