vonage
First post, but have to give a thumbs up to Vonage.
When I ported my old phone #, it took Vonage 3 months to get the paperwork done. They waived their monthly fee until it was changed over, so i was no worse off than before for 3 months.
911 is as simple as registering your modem to your home address. An extra step, but it took 2 minutes tops.
The ability to check messages online (and when you're away from home) is a big plus for me. Yes, you can get a high tech answering machine that would do the same thing, but it really is idiotproof.
Oh, and my bill is right at $27/month, unlimited calling local/long distance.
Call quality is great, but if you lose your broadband, you do lose your phone. So if you're having any kind of frequent internet outages, that would be the only thing that would hold me back.
Google around, you can find all kinds of free activation + 1-2 months free when signing up.