I think it's too early to tell. I'm in a similar situation: My DS's touch screen isn't really working all to well. I can pay $75-80 for Nintendo to fix it, $130 for a new DSlite, or $180 or so for a DSi quite a while into the year.
For me, the promise of what the DSi could be is making me wait a bit. Not to long in the past, I wrote something on these boards like "I want a handheld that's about the size of a gameboy micro or a cell phone, with onboard storage, and digital distribution." Well, nintendo's sorta come through.
I don't think that the promise of the Gameboy Micro showed through it's initial price, and took some time for people to realize its merits. I bet the DSi will be quite the same. So like I said, I am going to wait, and see what the pricing will be, what the DSware games are like, and probably, to touch a system in a store. If you are really interested in the DSi, you're going to need to wait too, because there just isn't enough information out there yet.