Howard argues with Howie. Heidi rolls her eyes. And Mel B? She just sits back in her chair with her arms folded, looking...Scary. Judging from our roundtable discussion in Los Angeles with the four panelists of America's Got Talent — returnees Howard Stern and Howie Mandel and newbies Heidi Klum and former Spice Girl Mel B — nobody's going to be singing "Kumbaya" this season. "Having the two ladies in the middle and the two Hs at the ends, it's working out great," says AGT host Nick Cannon later, at a separate photo shoot. "They've got great chemistry. They get along really well. And when they don't get along, it's even better, because it's so entertaining."