The word you are looking for is "scaling"; increasing
the image size by an equal amount in both horizontal
and vertical.
The new monitor is 16:10. Shows on the satellite
like SG1 and Atalantis are broadcast in 4:3 with
black bars (letterbox) top and bottom. So the actual
viewable image is 16:9. My current TV software
(Winfast PVR) will let me stretch the image
horizontally to fill the screen, but not vertically to
get rid of the black bars. So the image I'm watching
now IS distorted AND Letterbox.
Letterbox laserdiscs pose the same problem for wide
displays. Any w/s TV that lacks scaling is worth avoiding,
and this includes several recent LCD models. If there
were high-quality inexpensive aftermarket scalers available,
it would be a different matter, but I haven't found any yet.
It sounds like it's not a common feature of soft tuners either.
The reason wide TVs lack scaling is that it isn't trivial
to do properly. So anyone for whom it's an issue is
advised to bring test programming to the store, or only
buy when there's a return privilege.