I love Skillet and Red. Here are some that I like, too:
tobyMac, Flyleaf, Lifehouse, Run Kid Run, Pillar, Group 1 Crew, Kutless, Hawk Nelson, Jars of Clay, Thousand Foot Krutch, Downhere, Seabird, Remedy Drive, The Fray, The Almost, Mat Kearney, Stellar Kart, John Reuben, and Jeremy Camp. :)