"Hall" has been trademarked. What make you so confident the owners of those trademarks couldn't take action against you, and leave it up to half-chance that it could be taken away from you (even though you may not have infringed against it)?
There are actually ways that a knowledgeable person can dodge that (and yes getting your own trademark is one of them).
But there is an interesting paradox here. As noted by another post on this page vaksel had noted that "the most I was able to get from the 40 companies I contacted is $7,500" with relation to a domain name he was trying to sell that he felt was worth way more.
The paradox is this. If more companies realized the value of domains they would be easier to sell. But there would also be many more UDRP's and cybersquatting lawsuits than there are now. Many companies simply don't see enough value in the domains to even pursue a UDRP that can be done for probably $5000 (if the right firm handles the complaint).
You have a 1b intent to use application not a registered trademark
http://tess2.uspto.gov/bin/jumpto?f=doc&state=4010:55oou...
That being said obviously the trademark app is needed. But the fact that you are using the domain name and that there are actually multiple trademarks for "hall" and that it's a common term is the thing that offers the real protection here from predators.
Your attorney should have not filed this as a 1b though. It will take longer to get the trademark issued.
They should have advised you to simply use even a site mockup or beta site to create a screen grab for the application. (I have 21 registered trademarks).