#1 Paramore
To a lesser extent: Metallica, Ke$ha, Dev, Jeff Mangum, Cat Power, Alice in Chains, Regina Spektor, Dr. Dre.
As far as artists that still do shows, I've seen pretty much all my favorites. I'm finally going to get to see Neil Young & Crazy Horse for the second time next month. After that the artist I want to see a second time is Taylor Swift, hopefully there will be a tour this summer. I should really get around to seeing Metallica, they're the only really crucial artist left on my bucket list after Paramore.