I am watching this thread and would love to find some good solutions myself.
Windows Movie Maker has never worked very well for me. And, bizarrely, although I am a Windows user my beloved Lumix pocket camera shoots .MOV while my wife, the die-hard Apple worshiper, has a Canon that shoots .AVI.
I would like to edit those, as well as other "small" tasks such as cutting out small bits and scenes from other file types.
This seems to be a devilishly tall order that does not have a good solution. Some of the (supposedly) highly-rated ones such as Avidemux (sp?) are totally hit-or-miss for me and often do things like leave out sound.