A better list of the new features for the "DSi":
http://gonintendo.com/?p=57999
The only con is no more GBA slot, but since I have an SP lying around anyway, and odds are GBA games will end up downloadable, no skin off my bones. I won't be able to play GH: On Tour or migrate Pokemon anymore, but eh. The first game will get old eventually, and Pokemon Platinum will let me catch just about anything I could really want myself.
This thing will render my PSP useless, since it's main functions for me (music, pictures, and "emergency" web browsing) have been demolished with style by the DSi in one fell swoop. Good thing too, 'cuz I'll probably need to trade in my PSP and my DS Lite to afford this thing.
EDIT: Also, looks like that's the power button on bottom left next to the screen. Probably moved there to make room for the SD card slot.