S.B.
W. - Vonage is great if you rarely use your phone & instead rely on cell phones. My husband and I both primarily use our cell phones for any calls, but I just couldn't let go of a home phone number and so I switched to Vonage about 2 years ago. I don't use my home phone for much, really, so Vonage is pretty good.
If you intend to actually use your home phone for most of your communication needs, I don't recommend it. The service can be sketchy (regardless if your internet is up and running) and clarity on calls is pretty nonexistent. One pro to it - you get an email everytime you have a message. For some reason, I really like that feature!
If you're looking to just save money on your bill, look into package deals w/ internet, cable, and phone. I've heard they can be pretty good and take the pain out of such a high phone bill.