The undisputed kings of the '90s line-dancing craze, Brooks & Dunn are not only the biggest-selling duo in country music history, they've also sold more records than any other duo period, save for Simon & Garfunkel. Ronnie Dunn was the quietly intense singer with the soulful voice, while Kix Brooks played the part of the high-energy showman. Neither had been able to break through as a solo act, but together they hit upon a winning formula of rambunctious, rocked-up honky tonk with punchy, danceable beats, and alternated those cuts with smooth, pop-tinged ballads. The combination made them one of the most popular country artists of the '90s, and they were still going strong as the new millennium dawned.