I want one because I've had my Lite for years and am ready for a new one. I never got a DSi because I felt it didn't add enough to warrant a purchase at its pricepoint. But now the XL is coming, and that's an improvement. I want the bigger screens. 
I want all the extra stuff the i has over the Lite. The big stylus seems nice, too. Only downside is the colours, but I'll probably get the dark brown one as that one looks practically black.
Also, it's sexy.
@ Maneco: Yes, the sound is better. You should read the DSi XL article on Iwata Asks on Nintendo's website, it speaks about the machine, its features, its production and why it exists. Also a bit in there about the sound, and it's actually improved. 
*Edit: http://www.nintendo.co.uk/NOE/en_GB/news/iwata/iwata_asks_nintendo_dsi_xl_15513_15514.html
"Yoneyama:
Furthermore, we’ve also made it so that the sound can be heard more clearly.
Iwata:
I've heard customers who’ve actually bought the console commenting on the fact that the sound is much improved. What sort of ideas did you come up with to achieve this?
Amano:
The speakers in this console are actually identical to the ones used in the Nintendo DSi. But for the Nintendo DSi, the holes for the speakers were oblong...
Iwata:
There was just one small hole on the left and right.
Amano:
That’s right. But this time round, after consulting with Fujino-san, we made it so that there were seven small holes on each side.
Fujino:
A very important aspect of this product was that it should be easy to understand so I wanted to make it so that you are able to tell right away that these are the speakers. In addition, because the screens are much bigger, we naturally wanted to also increase the volume for the audio. But since the speakers are the same ones that we've used up to now, we pondered how to make the sound louder. Then after a process of trial and error, we made it so that it sounds louder.
Yoneyama:
So even though the speakers are the same, the speaker enclosure has a greater capacity so we’ve been able to make it sound louder."
