Contrast ratio really doesnt mean anything: If the brightness is 150 nits its pretty silly for contrast ratio.
Brand name is pretty silly too. Samsung has put out some generally good monitors with one or two bad ones. Viewsonic puts out generally poor monitors with one or two good ones.
Response time is also a farce. There are too many different ways to measure it which makes it inconsistant to base your purchase on it.
In my opinion, if it matters any:
First look for an LCD that handles DVI. If it doesnt handle DVI, you dont want it. Next make sure it displays 16.7M colors correctly. A lot of 16ms LCDs are totally wrong in this aspect - they are 262K colors.
Next look at the aspect ratio. a 5:4 resolution in a 4:3 aspect ratio doesnt make sense
After that, everything else is kind of gravy. Go with an LCD that has a high brightness and good reviews.
Kristopher