Toyfair is fast approaching. There have been a few leaks so far this year - the Fairy World, the Equestrian sets and the odd racing cars. That probably takes us through the spring releases, but the big release is usually the fall ones for the Christmas season. What else do you think 2007 will bring in new sets?
One thing I am willing to bet on is an add-on consisting of some or all of the older dinosaurs form the arctic series. They aren't in production otherwise (except the skeleton) and with the Dino theme it would seem a natural to have them as add-ons.
Western seems to be showing continual signs of life, and the Pirates are certainly due for a few new sets. Some additional shops for the modern series?