Part of it depends on your budget, your equipment, your video format, etc.
The Prosumer market would include Final Cut Pro X for Mac and Premier Pro (BBC uses Premier Pro) - Very powerful but a long learning curve.
Inexpensive Tool - Sony Vegas - Starts at as little as $49
Screencapture and Linear Editing Tool - Screenflow (MAC) and Camtasia (PC)
Imovie and Windows Movie Maker - Free with their respective operating systems.
Tons of them, just reflects your needs, your platform and your budget.