A lot of people have said that Punk was an era, an angry moment in time. It wasn't as much a musical sound as it was an attitude; an anti-social idea. I would consider most of these acts today not as punk, but as retro new-wave (or pop-punk). In that case the best punk acts have already been mentioned, like The Clash, The Buzzcocks, The Ramones, The Sex Pistols (and pretty much any band with "The" as a modifier). The newer acts should have a different category, because punk shouldn't be associated with a sound (if you're a U2 fan you know why). But, I can't stand it when music critics define a genre, or limit artists by placing them in easily referenced subsets, like grunge (ahhh... not that four letter word)... that in itself is punk, I guess.