I had no experience with Magic Jack, but as Frank mentioned, call quality is just bad with some devices, so as I mentioned before, be sure to look-up reviews for them if you go with VoIP.
I looked into clear for our new house, but it wasn't available, just for mobile devices.
I'm probably not as concerned about the 911 service as some. My parents have been traveling for about 15 years now and not had a land line, it's a matter of your own level of your personal peace of mind.
I think the phone company will do a plain old telephone service (POTS) if you push them to. The last time I went from the plan with all the bells and whistles ($44 per month) to just a POTS line (no caller id, call waiting, just a phone line) it was about $19 per month, but then they were going to actually charge me $5 per month for not having long distance on it.
That was the last straw and I vowed to get rid of them, not looked back. Again, it's your choice, your level of peace of mind, and your budget...just my .02