
Here's something that I think has been discussed countlessly on these forums but being new to the community, its something I wanted to bring up. I see the music of U2 divided into four era's: Boy - Unforgettable Fire, Joshua Tree/Rattle Hum, Achtung Baby - Pop & ATYCLB/HTDAAB.
First a quick summary to get you thinking (yes, as you no doubt know by now, I love summarizing U2 music

Into the Heart (1979-1985)
Ambitious, fearless, heartfelt. This was U2 taking flight for the first time; wide-eyed optimism and youthful bravado molding the chemistry and sound of the future. With explosive passion, somber melodies and heartfelt anthems it was the era of crashing drums, turbulent basslines, chiming guitars and yearning vocals. The songs were sketches, the visions were fleeting and the music was all about running, leaping and reaching out for the place as the best band in the world.
*Note: Even though their producers and sound changed for The Unforgettable Fire, the songs carry a simlarity with the previous era where the music and the vocals in the songs were more driven by the passion of the performance rather than the lyrics and meaning.
Luminous Times (1987-1988)
Epic, majestic, anthemic. This was U2 exploring the world around them; the music (blues, country and gospel), the people (Bruce Springsteen, Bob Dylan) and the world (American Southwest, Africa, El Salvador). No longer content with sketching the ideas of songs, the boys set about painting landscapes and skies with soaring, emotional and deeply spiritual music that would change the face of stadium rock for years to come.
Zootopia (1991-1999)
Dark, personal, bold. This was U2 exploring the world within them; the sonic architecture and limits of the traditional U2 sound. The songs were no longer sketches or paintings but graffiti. It was giant lemon mirror balls and black leather pants. It was drug-enduced fantasies next to heartbroken confessions. It wasn't about changing/saving the world but about changing/saving yourself.
Powerful and enduring; if the Joshua Tree/Rattle & Hum was the sound of a spiritual rising, Achtung baby/Zooropa/Pop was the sound of speeding back down on a roller coaster.
Signs & Wonders (New Millenium, 2000-2007)
Confident, melodic, enduring. This is U2 with an understanding of who they are and where they're going. Critically acclaimed and publically adored, this was the sound of U2, not returning to their roots, but bringing together all the experiences they have been through to their creating environment. Anthemic songs next to playful acoustics, adrenaline charged rock next to pleading ballads, spiritual acceptance next to rebellious angst. Its music as an expression more than exploration and its the chemistry of four Dublin boys with all the talent in the world.
Now of the four eras, on a scale of 1 to 5 stars (1 being poor and 5 being extraordinary) would you rate the music of each era:
Themes Explored
Musical Innovation
Ingenuity (as a whole)
Lyrical Depth
Live Shows (Stage, design, setlists, etc)
Bono's Contribution
Edge's Contribution
Adam's Contribution
Larry's Contribution
Music (Your own view of this era as a whole)
So.......whatcha think?