If you want to have a tool with which you'll be able to work more comfortably with YouTube, you can try out KeepTube. It's an application that will allow us to search for videos in this popular video web hosting service (as well as in many more), download them to our hard drive, create playlists with them and view them without having to be connected to the Internet. The player has support for FLV, MP3, MP4, WMA, and WMV.
KeepTube can be useful to store all the videos related to a specific theme in an organized way, so that in two clicks we can quickly access our favorite artist's video clips or the documentary about a specific subject.
Take control of YouTube with KeepTube.