I had to have a land line put back in for a couple of reasons. My directv receivers want the land line, although it seems you can weasel by that requirement if you're not doing sports packages, PPV's or the like. Also we had some misgivings about the cell phone 911 capability, and with an infant/toddler in the house didnt want to take the risk.
I played with VOIP for a while, but it seemed like the companies are all starting to fold and it frequently didnt work right, and that turned into a fiasco of multiple companies all pointing fingers at each other. I rapidly tired of being VOIP tech support middle man.
What I did get after much finagling and confusing steps (because confusing the customer is always your best sales tool), was a package from at&t with unlimited local and long distance and all the call features for about $40 a month. This had to be ordered online through a special link, with all sorts of funny business and addons I didnt want, but after ordering you could call them up and take off what you didnt want from the main, decently priced option and bring the price back down.
We could probably ditch the land line and change our mobile plan from the current el cheapo "tmobile to go" plan to one with more minutes and included LD, but i'm not sure we'd save a lot of money. I guess if you already use the cell phone a lot, the land line isnt that important.
We'd go from about $480 a year for the land line and $20-100 a year for the cell phones to about $500-600 a year for the cell phones and $0 for a landline. Pretty much a wash.