Ron is right, you get very close with a lot of finetuning, then you have to judge the print under the correct light afterwards.
I use a CG24" and a Spectraview 30", the latter has a huge gammut and is my main monitor, calibrated via Gretag i1pro. Very happy with the choice of screens.
Not sure why your current setup appears to be way of matching your printoutput, I don't know the Dell's, but I can say that your shortlist gives you somewhat best of breed, can't go wrong with that.
One more thing, you say you don't mind 24 or 30 inch, trust me, once you have a 30" installed you do not want to miss it anymore! With Lightroom for example, just fantastic, panels on the Eizo, and the full whack picture on the NEC, really nice!