RealPlayer

RealPlayer has always enabled you to play RealAudio (*.ra) and RealMedia (*.ram) files.

• Download videos from thousands of Web sites with just one click
• Build your own video library and playlists
• Play all major audio and video formats
• Flash Video support
• DVD, SVCD, VCD burning and video recording

RealPlayer for personal use includes audio CD burning capabilities, DVR-style playback buffering, multimedia search, Internet radio, a jukebox-style file library, an embedded web browser (using Microsoft Internet Explorer), and the ability to transfer media to a number of portable devices, including Apple's iPod, MP3 players, and Windows Media devices.

The best thing that you will find after installing it is the Flash videos Download Directly from YouTube.
It has an inbuilt plugin that enables you to download the video by showing a download video link right above the video as soon as you play the video.