I have owned a Nintendo DS for 3 years now and I don't regret it at all. It is a big step up from the Game Boy Advance. You can now go online with it and play people from all over the world, depending on which game you have. There is a large variety of games for the Nintendo DS, for kids and adults. There are even games that will work out your mind and even your vision! The new touch screen on the DS allows for some new innovative ways to play, never seen before in video gaming. You can now interact with your games in more detail than ever before. By this I mean you can draw, manipulate, and select things by just touching the bottom screen!
Not to mention this little system has the graphic capabilities of the Nintendo 64. When it comes down to it, the games are fun, the screen is bright, and you no longer have to buy batteries for a handheld, making this console worth every penny. You can also play Game Boy Advance games on your DS.
Nintendo just makes fun things and the Nintendo DS is no different.
Games I suggest are Mario Kart, Brain Age, New Super Mario Bros. and Metroid Prime Hunters.