Video Editing Software
I use sony vegas studio HD. Not expensive, very full featured and supports the video files straight out of the camera no conversion needed.
There are other packages in this price range but in my opinion no other had the feature-set/price balance of vegas HD. For 125 dollar you even get dvd authoring software (i don't use it that much, but handy at times) and audio-editing software (I use it a lot) with it. Some people complain that the learning curve for the program is steeper than some other consumer grade editors. I had no problems though, took me an afternoon at most to figure most out.