Well, I love the XL obviously (for now, that first-week hyperbole =P), but with how unfortunately low DSi XL's sell for now, it wouldn't make too much towards either. Yet at the same time it would also makes no sense to own three systems in the sameish line...
Maybe hold out for your convention then see about Black Friday deals? The Zelda 3DS was released last year for Black Friday, is probably the most beautiful 3DS out there, and is ironically worth more than any other funny enough. Not to say that something like that will happen again, but it may. I don't know, I'm horrible in making my own decisions much less helping others. =/
One of THE biggest things to look at though are the games. If there's not at least two or three games you want that are out right now, wait. Don't get it for something upcoming, don't get it for just one game. (Thank goodness it turns out there was actually more on PSP I wanted, got it for one game, and needless to say, I didn't like the one game. Yay. Birth By Sleep and Monster Hunter actually made it worth it though.) I know someone who got theirs for Animal Crossing because it was supposedly launching late last year or early this year. Well.... Yeah. He also wanted it for Luigi's Mansion. And now THAT's in 2013 territory. Verdict? Make sure what you get something for is already out.
Another random side-note, no one buy warranties from Gamestop for 3DS/XL's without thinking about it first. I bought a year's warranty for my system because I like to ensure I'm covered... Then it occurred to me, Gamestop will REPLACE my system, not fix it. If I have any issues with the system it'll go to Nintendo so I can keep my games and data, not Gamestop. Sooo basically I lost $20. And that's just annoyingly stupid when there's no one but yourself to blame.