We watched everything that we wanted too from day one. I was joking.
For the first 150 hours, we avoided black bars or any channels with fixed images. After 100 - 150 hours we watched movies with black bars, but tried to follow them with full screen material or the break-in DVD. We avoided channels like the "History Channel" during that time because their logo is very bright. We watched a lot of HD public TV, HD NFL football, and HD "Discovery Channel" after we reached 100-150 hours.
The football games have fixed images that are in the same location for much of the game. After the NFL games on Sunday, I would watch a lot of HD Discovery Channel, or run the break-in DVD. When we reached 500 hours I stopped using the break-in DVD, but I still don't like the History Channel logo. It has to be one of the worst in HD.
Some people just stay tuned to HD Discovery Channel when they aren't watching the TV. It has very few logos, and they are never on for very long. It's also on 24 hours a day in my area.