What's the best before editing format to convert to? I am making a production for my companies trade show booth.  We're going to be running 2 40" inch TVs one cycling a few videos of our products in production and one cycling through a bunch of product pictures.  Anyway...

I have a bunch of videos we want to use but they're all in different formats and resolutions (Taken with different cameras over the years).  Some 720p, some 640x480, some MOV, some MPG, mp4, avi, etc, etc...  I am trying to get away with free on the video editing (VirtualDUB, Handbrake, etc...) so I am forced into using different tools to do different things.  Well in my experimenting I am finding that some video tools open mp4 and some don't.  Some open mov but most not.  I'd like to keep the videos as "RAW" as possible because they're all going to end up on a 40" screen eventually.  So you can see where I want to lose as little resolution as possible in the conversions.  I like mp4 (H.264) because it's the format that my player (Roku 2 XS) requires, but there isn't much as far as free video editing tools that will open those video files.  What format should I convert everything into before I start doing my editing?

Thanks
-Craig
I would recommend downloading the trial version of Adobe Premiere Pro, and cutting the videos together in there. The trial lasts 30 days which should be enough to get the job done..

Premiere Pro can take almost any file you throw at it (so you can leave all your videos in their original format). This way you wont be loosing any quality by converting your videos to one uniform codec before you edit. 

Otherwise as a completely free solution Id suggest converting all your videos to 1920x1080p h.264 files. Then you can bring them into iMovie or Windows Movie Maker to order and export one final file. 

If you dont need the all the videos combined into one file (ie. if your player can play all the files on its drive continuously) then all you need to do is convert them to 1920x1080 h.264 files and load them on the drive.