Beatles vs. Stones. Biggie vs. Tupac. Kanye vs. Taylor. Who do you choose? And what does that say about you? Actually, what do these endlessly argued-about pop music rivalries say about us? Music opinions bring out passionate debate in people, and music journalists/critics Steven Hyden and Jordan Runtagh know this firsthand. They’re both obsessed with the biggest (as well as the most obscure) riva…