I do have a HD Box from comcast. They came and replaced my old one last week.
1. Are you using either Component or DVI out?
Component
2. Did you make sure to select 16:9 mode on the box menu? If not, here's how:
Yup, I followed the exact steps you went into. The guy who installed the box showed me how.
3. If you did all the above, and are still getting some HD programming with vertical bars, well, you cant do anything about it. Whenever you watch HD, you lose control of aspect ratios and stretching. If is broadcast in 4:3, then you're stuck with it. Most everything that is true HD, will be in 16:9, but sometimes on HD channels, they will "upconvert" 4:3 stuff to HD, and broadcast it, but they wont mess with the aspect ratio.
I guess I'll just have to live with this until everyone converts.
Thanks for all the great info.