This is a tough one for me but I will go with:
1. Bad. It's beautiful, long and the band can pretty much do what they want with it. It's just a perfect closer.
2. Love is blindness. I just kinda like the way that it closed out the album and the tour. It's like U2 meant it to be a closer all along.
3. Walk On/ Hallelujas. Really that song left everyone on a high note. I'm not as religious as U2 is, but the Hallelujas really felt right about the Elevation tour.
4. "40". What's so cool is how each band member exits separately and then the man who formed the band is out there last, as it should be. After all, he's the one guilty of forming this band in the first place.
I may have ranked them, but there isn't much separating them in my opinion. I've just always loved "Bad" and when I DJ'ed college radio, I always used that song to close out the station's broadcasting day at 2 am. It's a truly beautiful song and a natural way to close out a concert or your day in general.
I'm a little bummed that it won't be the one they chose for the DVD concert but I still love "40" too.