I am a total U2 fan both old and new the Joshua Tree is a Beautiful work of art it is also the 2nd most selling album from the 80's (just behind Michael Jackson)
I would say one of my favorite tracks off that album is Exit it still gives me goosebumps
Lyrically Pop was amazing beautiful lyrics on that album I have all the U2 CD's and singles and so on and so on I think at last count I had over 75 CD'd of U2
even the one they did w/ Brian Eno released under the name "Passengers"