Video Editing as in...Actual editing of video to make special effects and of the like...?
Or just transitioning, picture-in-picture, stuff like that?
I would recommend Sony Vegas, but for screen-recorded achievements, try Camtasia.
Windows Movie Maker is good at times, but if you have the other two programs and know how to use it, they blow that program out of the water. WMM is the best free program of movie editing software.