I do editing for a living (thats why i rarely edit my helmet cam material, and i when i do, i do a crappy and sloppy job of it).
Avid or Premier. Avid for pro level adjustments, and Premier for simple and fast non linear process.
Final Cut Pro gave me an ulcer, Final Cut Pro X made me sarcastically laugh.
Although i wont deny FCP's ease of use for a home user (if you willing to accept the havoc it plays on the blacks in your video)
For the record iMovie is a piece of junk. Even for a home user.