Apple send out 'Back to the Mac' media event last week. A few more hours will to go for the event (10am Pacific time, 20th October).
There is a lot of rumors what Apple will announced.
Next version of Mac OS X. Apple will show some new features of the next version of Mac OS X, most likely the code name will be Lion. It reminds me of the ThunderCats animation, we have Cheetah, Jaguar, Panther, Tiger and now Lion. Will there be Lynx and Snarf too?
There are people expecting a new user interface. It might not be available this year, but it will be coming soon.
MacBook Air. A smaller (11"), lighter and cheaper MacBook Air, since it was not updated after the first released in year 2008. Check the rumors.