If you are serious about accurate color reproduction, homogenous lighting and grey scale resolution the 30" is the one to get. It is the clearly superior device. The 23"in display is too expensive considering it´s a middle of the road monitor (with great design)
I agree that the 30" is the way to go but NOT because the 23" is "too expensive considering it's a middle of the road monitor."
Hear this:
Both the Apple 23" and the 30" are at the TOP of their games. Yes they cost more. BUT both also use a very superior S-IPS panel. They both have SWOP certification. They both have very finely tuned and well built C-LUTS. There are FEW monitors out there in the 23", 24" and 30" sizes that come close to any of these two macs.
I am in the process of buying a new monitor right now myself. I would go with the 30" -- two 23" are nice but the bevel and lower resolution really get in the way. The 30" is a great way to go. Then when you get a desktop you can put a 23" beside it and have a very sweet setup.
I can HONESTLY say that I have spent 6 hours researching monitors during the past 48 hours and probably 20 hours over the past two years.
The only 30" that comes close to the ACD is the HP LP3065 or the newer Dell 30" high gamut.
In the 23" or 24" areas (really these are both the same) the HP Smart Buy, the Dell 27 and the Dell 24, as well as a higher end Samsung Panel (PVA) are contenders but again, the 23" APPLE is at the TOP of its game even compared to these contenders.
Before you flame me back, really do the work and the research -- compare specs and prices -- and you will learn the truth about monitors: newer does not mean better given the current state of technology.