I don't even have a landline. Used to have AT&T internet, had a problem with their modem they refused to fix without me paying an exorbitant fee, so I can cancelled all my AT&T accounts and went to Verizon for my phone and ComCast for my internet. One of the best decisions I've ever made. So, another vote for cell phone.
Even with my daughter on my plan, we don't use all of the minutes alloted us every month (most of her chats are after 9:00 pm anyway), we have no long distance charges as long as all calls are within the continental USA.