Is anyone using Vonage? We've got a really fast cable connection (2.4 MBps) and we could save about $400/year if we went with a premium unlimited plan for $24.99. We could keep our same local number, plus we could set up local numbers in Fort Worth, Tampa, KY, etc.
They don't require a contract and you can get an adapter free from Vonage or free with rebate from Amazon. It wouldn't work during a long power outage, but the cable modem, routers, and (potentially) Vonage box are on a UPS, so two hours or so would be OK.