An App Store COULD happen. Though with iPad mirroring coming down the pipeline, I don't see the need (personally) for yet another App Store. I don't think I want to buy Angry Birds AGAIN. Mac, iPad, iPhone...when does it end?
I don't think the hardware needs much updating, like what everyone else is saying. 720p vs 1080p is really not a large enough difference to warrant a whole new device. I'd love to see Pandora streaming, and I think that's a real possibility. But I would not hold my breath for Amazon streaming, as awesome as it would be. The two companies are increasingly in direct competition with one another, from books, to music, to films, to television, and soon enough, to tablets. I just highly doubt they will build a competing service into their device. It provides a cheaper alternative to renting shows on iTunes via Apple TV.