I have about 40 GB of raw video (shot on a friend's camcorder, its .MTS format) that I would like to do two things with:
1. Compress enough to be reasonable to upload to Youtube
2. Keep reasonably high quality copies myself for later editing, potentially use in TV commercials, that sort of thing
I'd like to do both those things while maintaining the sound sync if at all possible.

How do I go about determining the best way to do this?