well it really depends on what system you're using and what you're editing for. i'll start system wise.
Windows:
Pro: Sony vegas pro (a lot of components and takes time to learn... once learned it's probably the best editing software out there) Noobie: Camtasia (very simple and easy to use, not many effects but can get the job done for simple edits and transitions.)
Mac:
Pro: Final Cut Pro - lots of features but very static (not many plugins and add ons from my knowledge...)
Noobie: Movie Maker - very basic but compatible with final cut pro if you want to upgrade projects, very similar to final cut but stripped of many features
Both:
Adobe. If you're doing any type of editing and have a diverse type of projects to do (example: motion graphics to film recordings) using a combination of adobe premier, after effects, and other adobe programs are for you. Not only are these programs great as standalone products, they work really well together as you can sync and move files from adobe programs effortlessly. Also, the main program you would probably edit basic files with [Premier] is a simple but very powerful tool and doesn't feel as overwhelming as a sony vegas does (sony vegas as a stand a lone is still incredibly good).
I hope this helped!