My brother and I were speculating about this. While neither of us have a Macbook, we're both planning on getting one. Some features that came up were:
Retina Display: Will it become standard, without any other option?
Flash storage: Will it be the only option, whether or not the Retina display is?
Quad-core: Will it come on the 13" too?
A few things he was hoping for were another USB port, and an HDMI port.
Will Apple come out with something completely new, or was Retina enough for awhile?
It's been awhile since the last one. Do you think the next come very soon after the new year?
What do you guys think? I haven't mentioned the Air, probably because I don't really care about it.