Green Day - American Idiot. It's not that I dislike what came after, but 21st Century Breakdown feels disjointed, the Trilogy has really low lows, and they stopped being ambitious after that and just put out two "pretty good" albums and one awful one.
Also even if you don't like their '00s sound, I seriously don't get why Dookie is more well-liked than Nimrod beyond "it had more hits and I heard it first."
21st is a mix of B-Sides from American Idiot and Cigarettes and Valentine's, put together to make it's own album, I don't see it as disjointed but I can understand why. For me it comes across as an aged Warning.
Uno-Tre was their way of screwing over their record label because they were contracted to do 3 more albums. So considering they pulled out 38 songs in that timeline. I'd say listening through 21st and the songs through Uno-Tre, it's pretty clear to hear the difference in production of the songs complexity. 21st has tons of diverse, almost orchestral elements supporting the background of the songs. Uno-Tre are generally a bit more simple in their compositions (as are Rev Radio and FOAMF)