ClipConverter.cc offers a free and premium download service for videos from sites like YouTube and Vimeo. There's a lot of competition, with opensource tools generally providing the most secure and privacy-focused options. Those free options might involve a more complex setup but some offer a graphical interface to make things easier.
Online tools like ClipConverter are the easiest to use. Just copy-paste video urls and get downloads. But native apps for Mac or Windows usually offer additional features like batch processing.
RipTiger is the easiest, most powerful way to capture web video. Just start RipTiger, play your video as usual and RipTiger saves it. No additional click or configuration hassle. RipTiger does everything automatically in the background for you.
Freemake YouTube Converter can convert YouTube to MP3, convert YouTube directly to iPhone, iPad, Android, PSP, iPod or a mobile phone. Download any YouTube video in AVI, MP4, FLV, 3GP, MKV. No registration, takes 3 miliseconds to do, absolutely free!
YtConv is free YouTube to MP3, MP4, 3GP and AVI (DivX) Converter and allows you convert and download a YouTube Video to MP3, MP4, 3GP, FLV and AVI (DivX) file online. So you are able to watch/listen to your favorite YouTube tracks.