Sony and Microsoft have both claimed that they don't plan to follow that model this generation (although it should be noted that video game companies are notorious for vehemently denying the existence of new hardware right up until the moment they publicly announce it, presumably out of fear of damaging sales of the current generation. Likewise with price drop rumors/announcements.)
Nintendo hasn't made any specific announcements about its plans, although it has denied every specific rumor about new hardware (but see above.) Despite that the rumors seem to be popping up more and more often over the past several months. From a financial standpoint they're undeniably in the lead this generation, which puts them in a temporary position of strength. But we've already seen with Nintendo from the NES/SNES days and Sony from the PSX/PS2 days that the current market leader can always fall from favor when the next generation comes around. Some people think Nintendo ought to/needs to use its position of strength to move forward in the console generation and a get a new product out while they're still on top. Others think that's too risky and they should be content to stay on top with this generation for as long as they can manage.
Recently Nintendo got into a row with one of the japanese newspapers over whether or not the president of Nintendo revealed details about the next DS, and Miyamoto just recently confirmed that there is some kind of new hardware being worked on. However "new hardware" could mean anything from a new console, to another revision of the DS, to the vitality sensor that we already know about. And of course it wouldn't be the first time if Nintendo decided to ditch whatever new hardware it was working on now without ever releasing it.
So lots of rumor, speculation, and opinions. You know what that means, right? Poll time! :)
Is Nintendo going to announce new hardware this year?
If so, when will they announce it?
If so, what kind of hardware?
If a console, what features will it have?
How much will it cost at launch?
If a handheld, what features will it have?
How much will it cost at launch?
Would releasing a new console be a good idea or bad idea for Nintendo?
(Why are "hardcore gamer" and "casual gamer" in quotes? Because most people (most people in the gaming community anyways) think they know what the terms mean, but no one can come up with a good definition that everyone agrees on, not everyone agrees on who belongs in which group, and for each term there are at least some people who consider it an insult.)
And as usual, if i didn't cover all the options you think should have been included, then comment on it! :)