The first U2 album I heard was Pride (In The Name Of Love) off of Unforgettable Fire. I immediately had their entire back catalog and listened intently. I love the album October the most. I wore out Unforgettable Fire and screamed how wide awake I was.
I saw them in 1987 in Oakland California for the Joshua Tree tour. The Pretenders opened. Johnny Marr of The Smiths sat in with Chrissie Hynde.
After that, they just got bigger and bigger and I pretty much just hear the new hits while clinging to the earlier albums.