What is the next big portable system?

Nintendo is bringing out an upgraded version of their handheld console, the Nintendo DS, called the Nintendo DSi. This new system has lost the old GBA slot and instead has an SD card slot for expandable memory. This is for the purpose of its other features, which will include a digital camera, web browser and downloadable games. I'm not sure about other companies, but sounds to me like this one's going to be big.

Kabalzo-PSP GO