Speaking as someone actually fighting eminent domain in federal court with Houston-based Spectra Energy, I can confirm that, nowadays, eminent domain has less to do with projects for the "public good," and everything to do with the financial good of publicly held companies.
In Bedford County, Pennsylvania (about 2 hours from Washington), property owners are being hauled into federal court by Spectra Energy, backed by the power of the Federal Energy Regulatory Commission.
The "public good" argument is that this is an underground natural gas storage site (bring gas from somewhere else, charge a fee for storing it, then send it to the northeast via piplines and charge another fee).
What goes missing is that the landowners' property is sitting on top of the gas-rich Marcellus Shale; but they can't develop that because Spectra Energy wants to use the Oriskany sands layer (which lies just beneath the Marcellus) for its underground gas storage facility.
In addition, Pennsylvania has more underground natural gas storage sites than any other state in the continental US, according to the Dept. of Energy.
Further, in its most recent motion, Spectra Energy asked that the federal judge exclude evidence that would argue "economic loss to the landowner" for fear that the jury would be "confused, misled and distracted ... waste time." (From p. 7 of the motion: Case 3:08-cv-00154-KRG, Document 59).
Here is the great conundrum in eminent domain: property owners possess the key asset that companies and government covet – the land. But they are treated as a waste product in this process rather than as key stakeholders.