Two of rock's most charismatic and poetic singers -- Robert Plant and Stevie Nicks -- square off for the right to advance to the finals of the 100 percent fan-voted Ultimate Classic Rock Hall of Fame competition.

Every month, our readers will decide which of eight legendary artists or bands will be honored for their contributions to the genre. This particular battle's contestants have a lot more in common that just great hair and a hippie-dippy fashion sense.

They both are, or were, integral members of two of rock's most important bands (Fleetwood Mac and Led Zeppelin, as if you needed that), and each also managed to strike out on their own with remarkable solo careers. Nicks took Billy Idol to school in round one, beating the 'Rebel Yell' star by more than a two-to-one margin, and Plant beat out Phil Collins -- his one-time guest drummer -- just as handily.

So who gets to move onto the finals? It's your call. You can vote once a day between now and Monday, Oct. 27, at 11:59 PM EST. This month's winner will be announced on November 4. Be sure to read our official rules.

Ultimate Classic Rock