I read somewhere that it is best to shoot reg screen instead of the widescreen (letterbox layout that DVX100 has set up in the menu) and make it widescreen in post by adding letterbox to the project - is this true?
I always shoot squeeze just cause I like how it looks. I am pretty sure if you shoot full screen you might get better quality video, but I never see a difference with anything I shoot. If you shoot full screen and add black bars in post you can also move your image up and down a little if you have to since the bars will cover up the top and bottom
If you try doing the search function here on dvxuser you'll probably get a plethora of information on the subject.
My take on it is that if the goal for your content is youtube or the likes it doesn't matter- shoot what's easiest and most convenient for you. If you're end goal is the big screen, and that's truly a possibility, then the choice actually deserves some consideration....