Engadget is reporting some stats that households are increasingly dropping their landline phone service for mobiles only. For safety reasons, I highly recommend against this.
… In the latter half of 2007, it was discovered that 16-percent of domiciles didn’t even have a landline
Mobile phones are great… until you need to call 9-1-1 (or anyone else in an emergency). They just aren’t reliable.
Also make sure you have at least one old, corded phone in the house. Phone lines carry their own power and may still work in a power outage. But you won’t know that if all you have are cordless phones plugged into an outlet near the phone jack.