Once upon a time, back when words like Bizkit and Korn were still spelled correctly, the Phoenix’s flagship radio station WFNX-FM (101.7) could be counted on to deliver the best of punk, post-punk, new-wave, alternative music. Then the nu-metal dudes muscled in. And before long, the station’s fare had shifted to what ‘FNX program director Cruz described to the Boston Globe as a "suburban angry white-boy vibe."

Now, as the station kicks off its 20th anniversary celebration, it’s recommuning with its past. As part of a concerted format change, this weekend ‘FNX will be transmitting "The Top 500 Ever," a ranked run-down of the best alternative rock of the past two decades. (It will be simulcast on ‘FNX sister stations WFEX-FM (92.1) in Manchester, N.H., WPHX-FM (92.1) in Portsmouth, N.H., and WWRX-FM (103.7) in Providence, RI.)

Old guard heroes like Echo and the Bunny Men, Depeche Mode, Boston’s own Pixies, and the recently Hall-of-Fame-inducted Clash will be interspersed with newer phenoms like the White Stripes, Coldplay, and the Soundtrack of Our Lives. Alt-rock behemoths like Nirvana, Pearl Jam, and the Red Hot Chili Peppers will also make their voices heard.

Even better, when the countdown’s over ‘FNX and its northern affiliates will continue to showcase intelligent, challenging bands like these all the time. (WWRX will maintain its present format.)

Log on to www.wfnx.net on Monday morning to see a complete list of The Top 500 Ever.