I have used them all and by far the best software out there for the average, and I am emphasizing the average user, is Camtasia Studio.
The learning curve is low, it has a ton of features, it works great with both screen captures and video cameras, it has a very intuitive studio editing software package, and the price is not too bad considering what it does.
It is not cheap, but then no good software is...
Adobe Premier is a great piece of software, but is very difficult to learn for a beginner, and unless you have a background in videography, many of the features you will not understand. It is a professional video editing package and as such has many features that the average person would never use. I also have never liked this monthly rental thing with the price. That monthly/yearly pricing model sucks. If you stop to really figure out what those software packages are costing you, it is insane.
I also do not like the compression algorithms with Adobe Premier. It seems that the file sizes are rather high using their compression settings and the quality is not improved with the higher file sizes.
Anyway just thought I would throw this in as I do a lot of video and use many of the packages that have been mentioned here.
As a side note: They have just released Camtasia Studio 9, as a member of TechSmith I received a copy about a month ago to go through and do some testing on. I was very impressed with the new features in the upgrade and the speed at which it compiles the videos. They have added a lot of new features, far too many to mention here but from what I have seen it is a really good piece of software.