If you read any gaming magazine, online forum, website, or blog, chances are, you'll come away feeling as if PS3 is doomed and that the Nintendo Wii will take over as the winner between the two of them. While the Wii may sell more units than the PS3 (or vice versa), one thing is being left out of all this pseudo-analysis.... the console manufacturers are targeting different audiences with them.
The Nintendo Wii is going after the casual to medium gamer who doesn't want to spend a lot on a gaming system but wants to enjoy the entertainment surrounding it. Games will probably be on the cheaper end of the 3 majors and you'll certainly see classic Nintendo games come back to life. With the Sony PS3, it's targeting a much more hardcore gamer though potentially a bit less than the XBOX 360 and appeals to the technosaavy high-end gamer.
People all over the world are saying that the PS3 is doomed but remember, historically, Sony has sold plenty of Playstations and this is a flagship product for them. Also, Nintendo with it's superb price point will sell well also. Research shows that console owners have more than one console - I'd assume plenty of people will pick up both a PS3 and Wii.