Personally I tend to upload rather than download from YouTube, but I am aware that there are those who tend to collect video clips off-line, by means of:
» ClipNabber downloads video clips from YouTube, Dailymotion, Vimeo, MegaVideo, and lots of other video sharing websites in 3GP, FLV and MP4 format.
» Gazzump is the ultimate youtube videos download application for downloading youtube videos in various audio and video formats. Some of these formats include MP3, WAV, WMV, AVI, MOV, MP4, FLV and many more!
» KeepVid is an ad-supported, but free-to-use, YouTube ripper for downloading YouTube videos in 3GP, FLV and MP4 format.