Vonage
I've recently switched home phone service to Vonage, away from my local cable provider which was providing basically the same service (VOIP) with less features for more money. A service I hardly used anyways. The most egregious bug/feature with the old company was that I HAD to dial "1" in front of every number with a different area code, while for numbers within my area code, I HAD to leave out the area code. Pair this with the fact that the caller ID service they provided didn't normalize numbers to account for their idiosyncratic and completely retarded system, and you have a major stroke-inducing situation at your hands.
Anyways, I made the switch and I couldn't be happier to have access to modern age phone service. I can manage my voice mail box from my browser and voice mails are emailed to me as a .wav attachment. I don't like voice mail in the first place so that makes it much more pleaseant to use this necessary evil. I am always delighted when competion and innovation create a benefit I actually care about.