This thread is about the original British version mostly, but feel free to discuss the US version too (I've never seen that version)
So season 4 begins with:
Things are really looking good for this series, i especially like seeing more of Tom and Annie (who are both ridiculously attractive) and the introduction of 2 more ridiculously attractive characters (Hal and Pearl). The idea of a ghost as a villain is also going to be very interesting.
If you haven't watched the British version, i highly recommend it. It has a lot of the same charm as Doctor Who does.