The Nintendo Wii is the only current-generation console that doesn't pump out HD content. It wasn't that big a deal at first, but it's made the console not age particularly gracefully. Which is why rumors of an HD Wii 2 coming out in 2011 make a certain amount of sense!
This particular rumor consists of a next-generation Wii in the works that sports both HD output as well as a Blu-ray drive, much like the current PlayStation 3. Now, the HD thing makes sense, but I'm not totally sold on this Blu-ray idea. For one, those drives are expensive. Second, I'm not sure if physical media will still have a place in the next generation of consoles, with makers instead moving exclusively to downloads.
Downloads, after all, basically kill off the used games market, giving a huge uptick in sales to publishers. So if Nintendo is really looking to kickstart a new generation, that might be a way they do it. But time will tell!