Today at 10am Pacific / 1pm Eastern, Apple will give a keynote presentation at the Steve Jobs Theater, part of Apple's new Apple Park campus in Cupertino, CA. We will definitely see the 2018 versions of the iPhone, and I expect to see a new Apple Watch. I'm sure that Apple will also say something about iOS 12, which Apple first previewed this past June and which I suspect will be released in the next week or so.
Other than that, I'm not sure what Apple will announce. For example, I expect to see a new iPad Pro this year, but I don't know if we will see it today. Sometimes Apple announces a new iPad and new iPhone at the same time, other times Apple holds back the iPad announcement until the next month.
Finally, it is always fun when there are surprise announcements, so I hope that something interesting is announced today that I wasn't expecting at all.
If you want to see the announcements live as they happen, click here to watch a live stream from the Apple website.