Which Screencaster do I use?
For regular desktop recording I use SimpleScreenRecorder (available pre-packaged for Debian, Ubuntu, and OpenSUSE)
On my system it produces a high quality recording without any latency issues, and best of all when I finish recording the .mkv file is immediately ready for use.
Install Instructions for Ubuntu:
$ sudo add-apt-repository ppa:maarten-baert/simplescreenrecorder
$ sudo apt-get update
$ sudo apt-get install simplescreenrecorder