It's been years since I cut the cord on my landline phone, and although there have been bumps along the way (anyone remember SunRocket?), I can't complain about the thousands--yes, probably a couple thousand, by my math--of dollars I've saved.
If you're ready to do likewise, I highly recommend the Ooma Telo. This sexy black box plugs into your router and provides unlimited local- and long-distance calling.
It normally sells for $199.99, but today only, and while supplies last, Woot has the refurbished Ooma Telo home phone system for $139.99, plus $5 for shipping.
Once you buy the hardware, you're looking at practically free phone service--forever. Your only bill will be for taxes and fees, which in my area come to around $3.50 per month.
One thing to keep in mind is that the Ooma Telo affords fairly basic phone features: caller ID, voice mail, and so on. If you want extras like a second line, three-way calling, call forwarding (in the event of an Internet outage), and greatly enhanced voice mail, you'll need Ooma Premier, which runs $9.99 per month. Also, porting your existing number costs $39.99--unless you prepay for a year of Premier ($119.99), in which case it's free.
So, yeah, Ooma does nickel-and-dime you a bit, but most of the extras are optional. And even without them, you can use the Telo with your existing phone system, no additional hardware required.
But how's the quality? I've been an Ooma user for over a year, and for the most part the service is excellent. Even with the Telo installed behind my router (rather than in between it and my cable modem, the recommended setup), call quality seemed much better than I got from Vonage. But I don't recommend Ooma's Telo Handsets, which I've found slow and buggy.
Although this Telo is refurbished, it comes with a six-month warranty. Even at $140, it may seem like a steep initial outlay, but if you're currently paying $40-50 per month for home service, it won't take long to recoup your investment. And after that, it's all gravy.
Update: I forgot to offer any comparison between this and the new MagicJack Plus. The latter is definitely cheaper (roughly half the price), but it's also pretty basic--and there's no Premier-like set of features. Stay tuned for more coverage of that product.