I've done the waiting-in-line thing several times, and even camped out (last year) in the mall, having arrived at around 8:30 PM the night before and realizing that if I wanted to get in line, then was the time to do it. My friend and I set up "camp" with two camp chairs, chatted amiably with the people on each side of us and had a more-or-less comfortable night in the mall itself (if we had arrived even a half-hour or so later we wouldn't have been allowed to remain inside, so our timing was really good). Overall it was fun! Unfortunately on that Friday after I had gotten my new iPhone 6 Plus, I didn't have much time to play with it as I had an important engagement later in the morning, a gathering which ran well into the late afternoon. By the time I got back home I was more than ready to simply crash into bed!
This year? Well, if Launch Day is indeed September 18th, I'll be out of town overnight the 17th/18th, so no way I could hang out in line. When I get back into town later that Friday I'll of course check things out at the Apple Store and at AT&T but won't be surprised if by then they're all sold out and I'll have to wait a while for the 6s Plus.....