I cannot remember the last time where I advocated a PC program, but I simply have to say: Tech Smith's Camtasia, the screencast recording and editing program, is incredibly good. It does everything I could think of in a screencast recorder, yet the UI is very easy to use. It's clearly the best desktop application I looked at in a while.
The killer feature, of course, is "smart focus". In post recording phase Camtasia automatically figures out what is of interest on the screen and zooms in. See here for a cast I created with Camtasia.
It should also be said that it comes at a price (300USD), but there is also a 30 day trial version that does not cripple the produced screencasts in any way (btw: I bought it). Kudos to the Tech Smith.