Its not really mentioned in the video, but the DSi will have a menu somewhat like the Wii from what i've read, also the games will be hot swappable (whoop-de-doo). The D-pad is also a lot better from the DS Lite (think of what the really old DS D-pad was like).
i have to agree to pretty much everything lbtlover said, i don't think its worth it to buy another DS just to have some extra features, like a camera. I can already use my phone( i believe IGN said that DSi's camera resolution is pretty much the same as a phones anyway), and i would bring my digital camera if im actually planning to take pictures. Also, if i want to listen to music, i would have bought an ipod already. The DSWare could be a selling point, but they've only shown cheap games that would only hold my attention for maybe 5-10 min. I also don't like that the GBA slot is removed, i many only have 3 GBA games, but its kinda nice to to have the option and convenience of playing GBA games, especially if i trade my old DS Lite for the DSi, as i won't have any way to play my GBA games. Top this with the fact that i barely even play my DS anymore, only on rare occasions. I most likely will not buy the DSi.
But then again, i bet that Nintendo will make a mario or zelda game thats only DSi compatible, then lean back in their chairs and watch the DSi's sales go up 500%. Or maybe they'll announce Metroid Dread for the DSi, that would be just cruel.