Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Video DownloadHelper - Browser extension to download videos from the Web
Minitube - Minitube is a YouTube desktop application.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
MenuTube - Do you enjoy listening to YouTube's podcasts, audiobooks, interviews or anything else that...
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.
Tubbler - YouTube Movie Player for Mac OS X.