tubezilla
free,easy to use and it works!
http://www.snapfiles.com/download/dltube…
follow the link and download the program (free of charge). Install on your computer.
When you first start the program, it'll ask you to choose the location to save the download video, so browse to your desire folder.
Next obtain the link of your youtube video and paste it into the URL. Hit 'Get Video' next to the URL bar