1. There is no such thing as too many backups. I've had two laptops stolen (years ago) and one hard drive develop the whirries and give up the ghost. There is no such thing as too many backups. Blank DVD's are cheap. Your work and effort are not.
2. Klaatu (his nom-de-podcast), a multi-media professional, likes Blender for editing video. He discusses it in podcast episode 3x08 at
this link. I've never used anything more complicated than avidemux for some very simple editing and mencoder and ffmpeg for conversions.