Ah, also, how do I tell 8 bit for 6 bit models? I do a little occasional Photoshopping, so probably the dithering wouldn't be welcome I suppose.
Probably have to check with manufacturer or some other source as to whether 6 or 8 bit... they usually don't volunteer that info up-front..
Almost all conventional 19" LCDs will be 5:4.
With the 930, your "bottom part darker" issue was likely due to backlight problem.... shouldn't be a "viewing angle" issue on that one like it would be on a TN panel.
"How black are the blacks" is always a concern, and TN Panels are the worst.... it's been improving for all types of panels, but none so far appear to be "perfectly black".
There is no "best" LCD. Each panel type is better at something than the others. You have to decide which is most important to you and accept its shortcomings.
Addendum.... adding to this rather than editing. When I saw "930" I was thinking ViewSonic 930 rather than Samsung 930...
The Samsung 930 IS a TN panel. Even if your sight-line is perfectly in the middle of the screen, you're likely to see both the top and bottom being darker. That is a characteristic of "reduced viewing angle" of TN Panels.
To avoid this, pick a LCD with a VA or SIPS panel.