It helps to understand the jargon when picking a monitor.
There is only one technology common on the market. LCD. Pretty much the only displays you can currently buy are LCD.
These come with a variety of backlights. LED backlit (the really thin ones), CCFL (Cold cathode Fluorescent Light) backlight (the common thicker displays).
What is important for you is the type of panel technology that excites the crystals. The most common technologies are in order of expense TN Film (every cheap monitor), PVA (some of the more expensive models), IPS (the high end screens), and PLS (Samsungs equivalent to IPS).
IPS / PLS screens tout wide viewing angles providing you with a consistent colour and tone. TN panels on the other hand vary widely with viewing angle making them impossible to accurately edit a photo. The other problem is TN is a 6-bit technology as are some cheaper PVA displays. They rely on dithering to reproduce the already restricted 8-bit colour depth your video card puts out.
As KmH already pointed out get an IPS display.
Also suggested is to get a calibrator with your display (they are around $150+ for an entry level model) as your display will drift in colour over time.
You can look up what panel types are used in various monitors here
TFT Central - LCD Monitor Information, Reviews, Guides and News Also take note that there's really only 3 manufacturers of panels on the market, so don't be surprised if you find some monitors in your searches that actually have the same panel. That doesn't mean you can simply go with the cheapest as a great part of what makes a quality display is the driving circuitry and processing behind it.