TV apps would be great. TV content, please pretty please.
Even knowing that the iPad 3 is due out this year-ish...I'd get an iPad 2 instantly if they announced that, only with an iPad, non-cable subscribers could use a Showtime or HBO app, with full VoD.
And.
And, I'd pay the regular rates you do on cable bills for those channels (usually around 10-12 for HBO, with others added in for a few more).
That said...if it's anything at all, it'll probably be something smaller in scale, like official Siri integration with available add-ons (like voices), or additional magazines/books/music that wasn't available prior.
in that regard, I'm hoping for Mad Magazine, textbooks (as many as possible, including new releases), and the earlier works of Black Sabbath (the 70s releases).
Also, I'd love for them to finally announce that OS 10.8 will be "iOS for home computers". There's no reason not to, really.