In case you haven't heard (it just happened in the last few minutes), Apple has sent out invites to an October 20 (a week from today!) special event focused on the Mac. The cat in the picture is a Lion, so I'm pretty sure we're getting a look at OS X 10.7 Lion.
What else should be happening? I'm not aware of any major Mac hardware rumors aside from the updated MacBook Air. If there's hardware beyond that, they're keeping it seriously under wraps.