Keep in mind that burn-in is uneven wear. This is cumulative over time. If you spend 50% of your time viewing the same bright static icon, regardless of what you watch in between, you can bet that eventually that area will wear unevenly. It's not as if flipping on something else after a long session just wipes out these cumulative effects. Obviously burn-in can be very overrated but it has happened to people. If you are after a dedicated gaming monitor you might consider something else especially if you think you'll be playing a lot of the same game (think DLP or LCD based sets). If you are an all around user that wants to enjoy some gaming along with DVD, SD, and HD then you will likely never encounter an issue so long as you set brightness and contrast correctly (AVIA or DVE calibration DVDs).
Incidentally, movies filmed in a 1.85 aspect ratio will show black bars depending upon overscan settings as a 16:9 ratio is 1.78. Those that tweak their overscan settings to lower levels (increases amount of information/resolution in the viewable area) will see them.