Cyberdemon:
The Monoprice is probably the most reputable reseller at the moment. They also have the same monitors coming from Microcenter, and Ebay under the names Catleap, Crossover, Achevia etc. Some vendors will let you pay more for the a monitor with no flawed pixels (AKA they open the box, check to see if theres any pixel issues then seal it back up) - but the monitor is so high res it’s very difficult to spot a bad pixel in normal use.
The other main differences are whether or not they have anti glare coating or glossy finish (personal preference, I prefer matte but many people think glossy “looks” better as long as you don’t have any awkward lighting in your environment) also some have more inputs than others, the cheaper ones just have a barebones DVI connection and that’s it. More expensive ones will have HDMI, displayport, etc.
I may go with Dell’s U2713HM. It seems like the best entry IPS monitor and is getting excellent ratings all across the board. The Asus PB278Q also looks like a great monitor, and is 100 bucks cheaper, but doesn’t have the color presets or USB ports. Hmm…