Connecticut State Sen. Martin Looney (D-New Haven) has introduced a short bill (PDF) that not only acknowledges the right of citizens to record on-duty police officers, it also provides for a civil action against police officers who violate that right.
That second part is important. A right doesn't mean much if there are no consequences for government officials who ignore it. Witness this case in Florida, where an officer erroneously tries to say federal law prohibits citizen recordings of cops. Even in states where courts have thrown out criminal charges, a cop who doesn't want to be recorded can still harass, threaten, and even arrest you. You may not be charged. But he won't be punished, either.
This is the first proposed state law I've seen on this issue that includes an appropriate enforcement mechanism. It would be great to see Congress take up a similar bill, under the First and Fourteenth Amendments.
CORRECTION: This post originally stated that the linked case above was in Maryland.