Just to be clear, there are tradeoffs:
1. VOIP service is probably no good during a power outage or other emergency. Likewise, there is much lower quality of service guarantee on VOIP vs a real land-line run by the phone company.
2. Your phone service is now tied to your broadband. So if your cable modem goes down, you lose both. If you have a cellphone this probably doesn't matter much to you.
3. Dialing 911 works differently on VOIP. Because you don't physically have a land-line, the 911 call center does not know where you are. You must be able to give them your phone number and physical location at the beginning of a 911 call because your VOIP provider is unable to pass them this information.
If you're ok with these limitations, VOIP is a great choice. I'm currently seriously considering switching myself, since Verizon (those bastards) want to raise the phone bill to $20+ a month for just local service with no features.