I for one think it's inappropriate to build any religious structure near this "Hallowed Ground" and here's why:
I heard that there were a lot of Jewish people that worked in the WTC. And I also heard that they were the reason that the "chickens came home to roost" if you know what I mean... So no synagogues.
I'm actually a believer that the devil must have had his hand in the events of 9/11, so I don't think the Church of Satan should be allowed to build one of their temples of dark worship near ground zero either.
From a strictly logical standpoint, I also have to disagree with the building of Christian churches. Would God (J.C.'s dad) have let so many good American christians die such horrible, fiery deaths if he was really a good God; Would he have forsaken them in their time of need? Dude had his chance to shine and he blew it... completely choked in the clutch. Seems to me, that God is NOT and awesome god and I don't want the worship of him anywhere near where those towers went down.
I suppose I could be convinced to allow the construction of a grand temple to Ashura Mazda at the site since he probably had very little to do with this particular event but I think it's unlikely that will happen.