I'm not a big LCD buyer and I'm not saying that Apple's LCDs are the best on the market, but they're hardly a ripoff at the current prices.
Browsing through the LCD listings at CDW (largest online computer reseller, so not an unreasonable place to look even if they're not the cheapest), you'll see that Apple's Cinema HD is the cheapest 23" LCD they sell. Although it has slightly lower contrast and brightness than a Planar display at about the same price, it's also considerably higher resolution.
The cheapest 1920 by 1200 pixel (not 1600 by 1200 23") display I can find is from Sony, and that's $600 more than the Cinema 23" with identical brightness/contrast specs (same screen).
The competition is much stiffer in the 17" range, though, and there are 20" displays that are probably a better buy as well.
Also don't forget that, like it or not, the integrated power/USB in ADC is convienent.