In the past eight years of his remarkable career, Keith Urban has raised a lot of kids. And by 'kids,' the country star means the hit songs that have put him at the top of the charts, earning him numerous accolades from Grammys to CMA Awards. Urban chose the best-loved offspring from his four platinum-selling solo albums for a new CD released Tuesday, titled 'Greatest Hits: 18 Kids.'

"I get asked a lot, what are my favorite songs? And I always say they're all like my children, so I don't really have a favorite," Urban tells AOL Music of his decision to subtitle the album '18 Kids.' "They've all been created out of nowhere ... and then they morph, grow and evolve."

The compilation includes 16 of Urban's biggest hits, from 1999's 'Your Everything' to this year's 'Everybody.' Two new tracks on the album include a cover of Steve Forbert's 'Romeo's Tune,' and a new version of his self-penned hit, 'Got It Right This Time,' a song undoubtedly about his wife, Nicole Kidman.

"The song's hook is, 'I think I got it right this time.' And I'm certainly at a point now where there's no thinking involved. There's a little more conviction than that," Urban laughs. "As the song has evolved, our marriage has evolved a lot. So at the very end of this song, there's an ad-libbed line that says, 'I mean, I know I do.'"

The singer and guitar virtuoso will wrap up his 'Love, Pain and the whole crazy World Tour' next month. But don't expect him to log too much R&R time before he hits the road again.

"I'm absolutely loving it," Urban says of his live shows. "I'm at a point in my life where I see what I have and where I've come from. And the road it took to get here -- I never imagined it would be so full of challenges and darkness, and ups and downs. But all of that stuff has made this moment so much sweeter for me. I get on stage with the most amount of gratitude I've ever had, and I think that's the greatest way to perform."

Urban and Kidman recently purchased a new home in Nashville, where they'll finally unpack boxes once his current tour ends and her current movie shoot in Australia wraps. But he'll gas up the tour bus again shortly after the holidays, hitting the road with Carrie Underwood for their joint 'Love, Pain and the whole crazy Carnival Ride Tour.'