VoIP it is
I did decide to upgrade to the Speakeasy OneLink VoIP service. It'll take a couple of weeks to install. I'll be sure to post here my experiences.
In related news, Asterisk@Home looks like something fun to play with. As part of my Speakeasy upgrade, I'm getting two more static IPs, so I might be inclined to fiddle with some more home-grown VoIP stuff. I've heard plenty about Asterisk -- one of the developers presented at OhioLinux the last two years. The main product has always turned me off, though, by pimping the Digium hardware as much as the software. Asterisk@Home purports to be an easy-to-use, all-in-one installation of Asterisk plus many optional add-ons.