Kara DioGuardi's written plenty of pop hits, turning love woes and triumphs into catchy hooks for everyone from Pink to Cobra Starship, Britney Spears to Kelly Clarkson and more. But when asked to pick her all-time favorite song from the pack, she doesn't hesitate for a second.

"[Christina Aguilera's] 'Ain't No Other Man'," she recently told Billboard.com, during a sitdown with editorial director Bill Werde at the Media & Money conference in New York. "It was a celebration of love, and I think a lot of my hits  have revolved around the other side, whether it's a breakup or it's not going that great. This one was really about her husband, how great he was and how happy she was to marry him...and I actually got to sing it at my own wedding." 

DioGuardi's wedding in July is just one of her many 2009 milestones. In January, the New York native became a household name after debuting as the new judge on "American Idol," helping to guide future recording artists Kris Allen and Adam Lambert to the top two. When DioGuardi returns to "Idol" in a few weeks, she won't be the rookie anymore. That role will be filled by comedian and talk show host Ellen DeGeneres, who joined the show after Paula Abdul's abrupt departure in the summer.

"She's  really excited," DioGuardi said of her new colleague. "She can't believe this is happening...we're going to meet up in December and get to know each other better. I think she's going to be a great addition. I can't even imagine sitting next to her."

That said, DioGuardi says "it's still a little strange to think of 'Idol' without Paula," adding that when she first heard she was leaving the show, "I was sad. You could tell with the contestants that she was really the heart of the show...I couldn't believe it, to be honest."

After her "Idol" initiation, DioGuardi wrote material for contestants Lambert, Allison Iraheta and Danny Gokey's solo projects. Most recently, she branched out from her pop roots to record with country stars Carrie Underwood, Rascal Flatts and Lady Antebellum.

DioGuardi also enjoyed a first in her other gig as an A&R executive at Warner Bros. Records -- Jason Derulo, one of the artists under her wing, scored a No. 1 hit on the Hot 100 with his debut single, "Whatcha Say." DioGuardi says Derulo's of becoming a star "are pretty great, because he has some really good songs to follow up that single. In the pop market, that's what you need."