While the Wii is the console in Nintendo's lineup that gets most of the attention for its sales, the DS is always #2 on the US sales charts, month after month. In fact, last December, the Nintendo DS was the first system to sell 3 million units of hardware in one month. With the DS, Nintendo has proven itself the undisputed king of portable gaming, and the company's secret to dominance is simple: constant hardware updates.

Look at how many different variants of the GameBoy there were–like the Advance and the micro–well before the DS grabbed the throne. Then there was the DS Lite, and the various special editions. A serious Nintendo fan might purchase and/or trade in multiple units of each piece of hardware, and Nintendo is hoping that trend continues with its newest update. The DSi is the new iteration of the DS that drops the GBA slot, adds stronger wireless functions, and carries a $40 price increase.