If you use YouTube frequently then SMTube might become one of your favourite softwares on Linux. It is actually multiplatform but I was looking for a good app specifically for browsing and playing YouTube videos on Ubuntu. It uses the powerful SMPlayer to play the videos and hence is not dependent on flash. As a result the video quality is pretty good specially in case of high resolution videos. You can browse, watch and download videos with the ability to choose the video quality yourself. During my trials I found the video browsing pretty fast.
To install on Ubuntu:
$ sudo add-apt-repository ppa:rvm/smplayer $ sudo apt-get update $ sudo apt-get install smtube