MTS telephone and DSL up and running. I have to say again that they were a lot easier to deal with than Bell or Execulink. I am typing this on the laptop - just plugged it in and grabbed a DHCP lease and it worked. A little worrying that it hasn't yet asked me to enter any kind of authentication information; I don't know if that means it's the box labelled "Actiontec" (probably a router plus modem, but not labelled as to its function) doing the authentication, or if I'll have to figure out the authentication protocol once the current lease expires.
Normal mail delivery, and things like the chart service, won't resume until I get my main computer unpacked and set up; but at least now I feel comfortable transferring big and sensitive information with the laptop in a way I didn't want to do while I was a guest on my neighbour's wireless. (Thank you, neighbour!)
ETA: Shortly after the MTS installer left, the apartment management put my completed lease papers under my door, and that enabled me to finally go pick up the package that Canada Post has been holding for me since December 31 (I needed the lease to prove I really live here). The package turns out to be a DSL modem from MTS. So now I have two.
ETA: Desktop machine up now. Not networked, and the firewall isn't up yet, so I'm still typing this from the laptop. There was a scary moment there where I couldn't remember my own password on the main user account (it is, naturally, a password used nowhere else, and I hadn't had a chance to use it since taking the machine down in December); but I still had root, and remembered the missing password before I needed to seriously think about setting a new one anyway, so that was okay.
ETA: Bit of a snag here. The firewall machine doesn't want to boot, at all. When power is applied, the power light doesn't come on; neither does the power button work. But the power supply is producing what look like the right voltages, and if there's a USB key inserted, the light on that flashes, so there's definitely some power getting through. It's possible that the bumping and temperature cycling of the move dislodged something and I can fix it by carefully re-seating all connectors. I sure hope that's the issue, because I'm not sure of much else that could cause these symptoms while still being fixable.