For those of us who haven't switched to an entirely cell phone household, the traditional Baby Bell phone lines can get mightily expensive. Where I live, the minimum household line costs for a basic line add up to about $43/month with taxes, and that's with no long distance charges!
Assuming you have a broadband connection, the solution is obvious: VOIP (voice over IP). Using VOIP, you get to keep your current phone and phone number, lose no voice quality, and pay a lot less. VOIP offerings range from about $15/month for limited minutes (Vonage) to a high in the mid $30s/month for old monopoly offerings like those from Comcast. Skype, a European favorite, offers per-call pricing that is competitive with the best phone cards. You can also do voice-voice connections at no charge, of course, but for dial-in services (i.e. a number people using phones can reach you at), you'll have to pay. The best part is that your number is portable - just take your router with you anywhere you've got a broadband connection, and you've got a home-location phone while on vacation 3000 miles away (or, you can use a software phone and not bother with the router; their availability depends on the provider you choose).
Vonage is the best known of the VOIP companies due to their ubiquitous marketing.
Packet8 (below) generally gets better user reviews and has equivalent service for a cheaper price.
Packet8's $20/month unlimited plan will save you at least $250/year over you basic land line fees. If you've got a broadband connection and don't otherwise need a physical land line, I can't recommend them highly enough.