Sony Vegas Movie Studio HD
Want to edit HD video on the cheap? Sony Vegas Movie Studio HD 9 can do that. The program is affordable, relatively easy to use (if you understand basic video editing), and has all the features most users will ever need.
I did run into some issues in my limited hands-on: For some reason I couldn't create a project in the My Documents folder (mine is not in the default location), and the program did not support either Avid's Dazzle or Pinnacle Studio MovieBox HD capture hardware. If you intend to capture video via S-video or composite, make sure Vegas supports the hardware.
Note: This link takes you to the vendor's site, where you can download the latest version of the software.
--Jon L. Jacobi