Back in September of this year, the ISW reported that the Massachusetts Department of Agricultural Resources was considering banning a list of more than 140 invasive plant species. As of today, after a period of public comments, the DAR has officially enacted the ban, which will go into effect on January 1, 2006 (with 14 ornamental species receiving either a one or three year extension). You can view the official list here. To answer the question raised in the September ISW post, until a good way of assessing the invasiveness of cultivars and varieties is found, they will be considered invasive if the parent plant is invasive (whew!).
This may push Massachusetts right to the front of the line with regards to invasive plant regulations, at least in New England. If your state has done better, I'd be interested to hear about it - post in the comments below.