Well, I don't know what it should be about, but I have faith in James Cameron to deliver.
He is after all, one of the few men who delivered a sequel that was better than its already great predecessor. In Hollywood, that's a rare thing.
Also, he's a notorious perfectionist, so I don't think we'll have a rush job on our hands. Yep, I'm looking forward to it indeed. He's been planning a trilogy all along, so I guess it'll all come together.
Needless to say, I loved the first. Perhaps too much actually, I've seen it 4 times and I'm not bored of it. It's just got this great sense of wonder about the whole thing. Reminds me of my childhood.
Hell, the second might do an Empire Strikes Back and be even better than the first.