Nothing beats Final Cut Pro. It's the best editing software I have found.
It's extremely easy to use and supports a lot of different formats. I have edited quite a few commercial projects using FCP and After Effects.
You might also want to use mpeg streamclip software for import/exporting/converting video formats.
If you want to include titles, motion graphics and other super cool effects in your video, then you might want to invest time in learning Adobe After Effects.