I still have my wireline.. because of the alarm system, and for redundancy during emergencies. I would argue that the wireless is cheaper, because of my calling profile. The long distance charges add up fast. If you don't make LD calls, then it's another matter. It's something you need to do a bit of homework on. Sprint's deal for shared minutes is pretty good, although with crazy pricing structure, it makes the most sense to go to the $85 - 2000 min plan, as the 2nd phone is free on that one, instead of getting 600 mins and paying $20 for the 2nd shared line. I have 2 spare phones (older ones) that I kept after the upgrade to vision. Also -- sign up for Sprint 5 cent LD plan and 50min free plan which is free if you have PCS from Sprint. so, even if I do make the occasional LD call on the wireline, chances are it won't cost me much. The extra discount on the wireline with sprint made a difference in selecting carriers for me.
For those of you who need fax/alarm capabilities but want to remain wireless try www.telular.com, I have used their terminals for years...at one point I even had one of the most premier real estate properties in Hilton Head working completely on these terminals for about eight months...(about 40 units). Talk about a busy cell-site.
Of course landline phone service is cheaper than wireless for a family of four who makes mostly local calls. BUT for some of us single folk -- especially those of us w/ friends and family spread out over the entire country, wireless only is more cost effective than having both. I went a year w/o a landline, and then six mo w/o wireless. I have both now, but I'd give up my landline before I gave up my cell.