At $20K/year, I would expect a lot more households to itemize. I'm trying (and failing) to calculate off the top of my head what kind of mortgage you'd have to have for a similar deduction. But it's gotta be pretty damn big if your interest is $1600/month.

Well, if you are required to prepare your own tax returns through an accountant then he will most certainly, itemize deduction, you'll be asking him to get your tax bill down a bit. Power of incentive is nothing to be questioned.