There's static contrast ratio and dynamic. A 1000:1 static is considered as good enough. The dynamic contrast ratio- the bigger, the better. I'd look for 20 000-50 000:1 unless it is with LED technology which allows mega dynamic contrast ratio (MDCR) which equals to 2 million to 10 million :1.
For gaming you need better response rate. 2 to 5ms is good. 2 is best but it's marketing trick because there's no real 2ms yet (it's about the pixel changing from black to white to black again... and those with 2ms are gtg= gray to gray which is not a real response rate if you put it on a test). Also you'll need better FPS... unfortunately in this category the CRT's are still better (excluding 2 new models allowing 3D with 120mhz but those are a bit expensive...). Also note that 16:10 compared to 16:9 gives you a bit more height which is good for gaming, cuz u will want to have more space to look around but takes more time for the monitor to refresh the pixel. Also you want to know that the human eye doesn't make difference between the 75mhz and faster onces, really. Also the human eye can't make difference between a 2ms response rate and 16ms ;-) (I was in a shop yesterday and the selling guy made a test in front of me on samsung xl2370 which has 2ms response but on test it showed 15-16ms...)
Pixel Pitch is the distance between the pixels. The bigger, the better. 27+ is good. You'll see a bigger picture. What I'm not sure is if the pixel pitch is lesser would the picture be a little more detailed and color intense.
Anyone corect me if I'm wrong. I'm also making researches lately since I'm looking to change my old CRT.
Important: monitors which are considered cheap ($100-$500) in most cases use a TN matrix which is the cheapest one, combined with a fast response rate makes the colors not as good as if the response rate is a bit slower. That's how I changed my condition about buying a 2ms monitor. Now I'm looking for a 5ms one and I'm sure I'll be good.
1. DCR (or MDCR) is all marketing.. A SCR rating of 1000:1 is excellent.. One more aspect to consider here is the type of panel used.. They are generally of three types - TN, PVA and IPS.. An IPS panel based monitor gives the best picture quality and contrast ratio but they are costly (TN panels are the worst with image quality but are cheap to manufacture).. As for response times, a monitor up to a 12ms response timing is good for fast motion video and gaming.. Also to consider is the input lag ( difference between the time a signal is input into a display and the time it is shown by the display ).. TN panel monitors are excellent with response times and input lags, PVA panels are the worst..
2. As explained by turbonet, pixel pitch is the distance between the adjacent pixels.. Lower the pixel pitch, lesser is the grain amount and thus more clearer and crisper pictures..
3. Refresh rates are a no worry concept.. The video card just needs to produce enough frames per second to match (or exceed) your monitors refresh rate for you to get a smooth gaming experience..
With LCD's the concept always is - bigger the better.. Check out the BenQ V2410T.. It does not sports that many connectivity options (DVI and D-SUB only i guess) but bears a cool price for a 24 inch display..