There's an Apple event going on tomorrow! We'll be liveblogging, of course, but it's still up in the air whether Apple will stream video live, like they did for the last event. If so, well, we'll be using that too.
The most likely announcements are OS X Lion, which theoretically should bring more new features, rather than just speed and architecture improvements in Snow Leopard. Rumours for 10.7 include more iOS-integration and even iOS-like functionality in the OS.
You also have the leaked photos of the MacBook Air, a machine that hasn't been refreshed in so long it looks like a Geocities web page in comparison to everything else.
The rumours for the Air include a big-time battery, lower price, two sizes and weird storage. Seeing as the Air is the specialty notebook, it makes sense for Apple to do some weird testing on this model.
Another semi-likely thing is the Verizon iPhone, which is rumoured to be on the final testing stage before release. This points to either a pre-Christmas launch, or an announcement now for January that will prevent people from buying other phones on Verizon for the holidays.
iLife '11 is pretty much guaranteed, as is some kind of mention of when iOS 4.2 will hit. That makes for a pretty full docket of announcements.