Belligerent
Greekus Urungus
Alot of bands lost their luster for me after my teenage years. Few would be Pearl Jam,Dave Matthews Band,Sublime. All of which I used to love when I was younger. As far as metal, Id say Metallica and Danzig.For me the most mature bands Ive listened to are Iron Maiden, Faith No More and Pantera. Iron Maiden have proven this especially on their last three albums, which I consider as the best heavy metal records ever made. Faith No More dont need any further comments, King For A Day... is a festival of maturity. Some might say that Pantera was far from being a mature band, but Id disagree. Anselmos lyrics addressed many different topics in many different ways/styles, the music was excellent. Far Beyond Driven is also a feast for me.
As for bands for kids, I dont think hyena had in mind bands like Fall Out Boy, but rather the bands one listens to in teen age (good bands mind you), which lose their attractiveness once the person grows up. I think The Offspring is such a band for me. I liked them a lot, and still think their first 4 albums are very good, but I havent listened to them for ages.