Just returned from BKK, safe and sound!
According to the locals (spoke to a few taxi-drivers and the concierge at hotel), avoid the area which is closer to the political buildings (nearer to Asiatique, riverfront) which may have some small protests. The local daily in Bangkok also reported a rally on 10 Dec 2013 which would be held outside Bangkok that expects attendance of some 10,000 people.
We visited the Maeklong Railway Station, Damnoen Saduak Floating Market, Siam Area (Siam Paragon, Siam Square, Siam Centre, Central World, MBK), Chinatown, Sikhumvit, Thong Lo, Asoke, Phrom Phong and the weekend Chatuchak market. It was peaceful throughout and felt completely safe throughout our trip. Nice friendly people, AWESOME food!