I'll attempt to conserve words here: American Idiot is an amazing album. It just goes to show you that you never really know what people are capable of (well, I did, but that's kind of beside the point).
Based solely on "Know Your Enemy," a song I've listened to about nine times this morning (another perfect three minute Green Day song, with lyrics so simple and potent that they're white-hot), I feel pretty confident in Green Day having learned the virtues of competing way above your expected weight class. That is to say, 21st Century Breakdown, which was a hotly anticipated album of mine, is now the big thing for me this summer, with the exception of the release of the new Star Trek movie.
Go here. Listen to it. Don't even watch the video (which is a great video, by the way - it's smart, simple, and beats you over the head and through the heart with its point, just like the best Green Day songs). Listen to it again. Maybe even one more time. If you still don't feel it, well, you can't say I didn't try.