Hell no. There are many reasons why I would never buy one.
1. It's bias against fat people. Wii fit's is geared to lose weight. It is keeps track of your BMI as part of the program. And oh are the "obesity experts" toting it. (check out Judith's comments on African-Americans, they are a hoot.)
2. It's sexist. Wii Fit is geared for women. Sure there is a token guy on the website but Nintendo is gearing them to women who they feel don't buy Wii's. In the end they don't care if you lose weight, gain weight, end up with an eating disorder or it ends up sitting in your closet, as long as they have your money.
3. It encourages people to stay indoors and play videogames when they could be doing a fun nature walk that wastes no electricity.
4. It's a fad, it won't last and in 6 months when people have put their units in the closet because it is boring and/or they haven't lost any weight, I will still be walking, no matter if I've gained or lost. Remember Curves? The one by my house is gone.
So save your money, this is just another wasteful home gym.