I know it's M$, but Windows Movie Maker is, I feel, a very well put together application and while it suffers from a slight lack of advanced functionality for more complex stuff, it pisses on Adobe Premier when doing the simple stuff. A fade transition in Premier takes a few minutes - WMM takes a drag and drop. Also, the preview window in Premier is very hungry and starts to stutter after a couple of minutes of playback - no such issues in WMM.
I usually do the simple stuff in WMM and add any credits or overly complicated transitions in Premier.
Also like:
Firefox
Fireworks
Google Earth
Trillian