demo rooms.... remember that they are set up by pro's with calibrated screens and prefect lighting so can make it look better than when you get it home.
they are good tho for you to take in a few of you favorite dvd's and play bits of them on to get an idea. eg it may be showing Avatar on BD and the colours look amazing but how will it look when you put on Saving Private Ryan or The Matrix for example.
i would take in a few you watch and skip to bits that you know how it looks for you eyes now...
eg monsters inc to see how it handles Sully's Fur
The Fifth Element when they have the opera singer on stage infront of the earth.
The Matrix for some of the dark slow mo stuff.
Saving private ryan beach scene fast paced camera changes and natural colours.
something old that has been put on dvd but the film quality was never great to start with.
Also Digital Direct have the 503 listed. you just need to mail for the price.