It's also worth noting that you can buy a DSL modem fairly cheaply- I got one from amazon for about thirty bucks. This lets you bypass the equipment rental entirely. Of course, when (not if) it breaks, you have to fix it, and you have to be ready to set it up yourself. The sonic tech installed the wires and made sure my box was working, but then it was up to me to reconfigure the modem so that it worked with my router, and so on.
I'm paying about $50 a month total, including taxes and whatnot. Totally worth it.