Standard Definition is 480 lines of resolution. The television's panel is 1080p lines of resolution. Watching SD signals on an HDTV is a bit like zooming in too closely on a picture on your computer.

I'm not sure what constitutes "reasonable and acceptable" images, and I can't really argue anyone's perception, but standard definition is a lower resolution than what is designed for the panel. While technology is there to improve the upscaling of a SD picture, there's only so much clarity a television can add through processing the picture.

Digital TV doesn't equate to HD television, it just means the signal is comprised of 1's and 0's, rather than the analog wavelength channels. What would help most is High Definition.

And that difference is seen on the display. One suggestion I would make would be to go to your local retailer, and ask them to turn the TVs to a few Standard Definition channels or hook up a DVD player (not Blu-Ray) so you can view all of the televisions to see how they handle a SD picture. I would wager that the result will be similar to what you're seeing on your set at home. Not all retailers have access to Standard Definition signals, so if not where you purchased it, go to a retailer that can demonstrate this for you.