All our team uses Camtasia Studio to record our MSDN Nuggets (super exciting screencasts on MS technology!) and we all recently moved to Vista RTM which caused us all to face the same frustration and problems wth recording our nuggets - they just don't work (well video does, or audio, but not both)!
Thankfully, Casa dé Hambone has been facing similar challenges and documenting them on his/her blog and posted a link to a Beta version of Camtasia Studio 4 which works with Vista. So, now I can get record video and audio at the same time without too much interference. Pity, that it took me this long to find a solution and with 2 events this week to do the pressure is definitely on before the end of the week to get a couple of screencasts out the door! 🙂