The Videos are mainly from my Flip and are in MP4 format. Native to the apple but not the PC although it will read them. This is my summary
iMovie (Apple) - Seems to work OK. Haven't tried to overdub commentary yet which is an important thing. Have upgraded to iMovie 11 but haven't used it yet. I'm a bit scared of being to committed to the apple as I don't want to get stuck in their format.
Windows Movie Maker Live - This is the latest version of Windows Movie Maker but have had problems. It started out OK with the MP4 files but as the project got bigger it stalled and some of them. Seemed to run out of memory (computer has 4GB). Kept restarting to clean out the memory and finally got it to save the project. The other big issue is you can't overdub commentary unless you record a separate MP3 which is to complicated and to much trouble. Don't plan to use this again.
Window Movie Maker 6.4 - I have this as well and seem to remember it worked OK. Will try again with it.
WinDVD - Made a DVD OK. Want to see if I can put several projects on one DVD. Probably can
Editor that came with the Flip works fine but not much good for adding commentary, captions etc. Fine for posting something on YouTube quickly.