No, you don't have to keep the phone. If you really want a home phone service, you can get a VoIP service (like Vonage). The issue with 911 service and VoIP has been resolved because all VoIPs are required to register your number with your home address so that in the event you have to call 911, the dispatcher is given your physical address. You actually fill out an address verification when you sign up.
We had Verizon home phone service but canceled the service last year after many, many problems, incorrect charges and a problem where they actually gave our existing number to a new customer who started giving it out to everyone they knew! We still get calls for him and our number was supposed to be unlisted!! The Fios people have been in our neighborhood for over a year, pushing this new service. We finally told one salesperson that if he didn't get off our property we would call the police. There are many elderly residents on my street and most have been conned by Verizon sales people and then very, very disappointed by the Fios service and price, claiming that they aren't getting what they were told at the price they were promised. Needless to say - I am very against Verizon.