I know this thread is pretty old but I wanted to add my two cents worth.
iShowU (
https://www.shinywhitebox.com/home/home.html) has done me proud a number of times and I just registered it today. For $30(NZ) it's great value for money and best of all it's developed by a New Zealander. Buy Kiwi made and blah blah blah.
It captures video and audio either from system, microphone, or both. It has an interesting feature called Follow Mouse which will move the capture according to where you move the mouse but this can be a blessing as well as a curse. The capture area is easily set.
It can save in a number of formats but it doesn't seem like it will save to Flash so some conversion looks like it will need to be done, although it does save to YouTube formatted MP4.
All in all a worthy application.