Apple displays are hardly the best. Not even close. If you like the look, and more like NEED the look, buy the ACD. There are better displays that are cheaper. And there are better displays for "pros" than the ACD. Eizo, Lacie, NEC, etc.
And to say a pro (the target audience) doesn't need the things the Dell offers is foolish. Hell, you are talking about photographers, what photographer wouldn't want a card reader? What video editor wouldn't want other inputs to do video? Heck you can't even put an analog signal into these things without a $300 box.
Firewire... Apple doesn't make an iSight anymore which was a major reason to have FW on the LCD. Plugging a external drive is moot when the computer has firewire, not mention firewire 800.
The 23" has the following problems: Pink cast, image persistence, ghosting, etc. It also happens to have an outdated panel along with being overpriced.
And to the person who says how can two panels be different (visually I am assuming) if they use the same panel. Well, it is about the electronics. The panel simply has pixels and certain properties like black level, viewing angles, color etc, but the hardware behind that is what does the "right stuff," LUT control is one aspect of this. Proper scaling is another. Simply put, the bulk of a displays quality in derived from the behind the scenes stuff. A good panel helps of course, but lets take Eizo for example they use *VA panels in some of their displays. These display have great viewing angles (same as IPS), better blacks, but the color isn't as good. So, Eizo compensates with better electronics to make that display perform wonderfully. You could have the best panel in the world but when you stick the electronics from a General Electric LCD in there you can guess what the result will be.
That said, the ACDs are nice, but don't be fooled by those who purport it is better because they love the aluminum.
Oh yeah, backlight. bld44, the new Dell 2407-HC and the 2707-HC use a better backlight system than the ACDs. Also, tack on terrible backlight bleeding to the list of problems with the ACDs, not just the 23" either. Furthermore, Apple is using the same backlights everyone else does. Hence the backlight bleed, which is more a feature of poor manufacturing, but also inherent in the type of backlighting being used today. LED and SED will start to take this away.