Who's the most important Chili Pepper? The popular answer would be Flea, the nihilist bass virtuoso whose hard-edged funk work-outs defined the band's sound for more than 20 years. Sure, Flea is pretty badass, but my vote goes to on again/off again (currently off) guitarist John Frusciante, whose knack for melody and mood is the common denominator in the band's best works (Blood Sugar Sex Magik, Californication). Frusciante's fretwork is sorely missed on I'm With You, a mediocre effort that could be a concept album — if said concept entailed making a record without any actual songs. Anthony Kiedis seems content to let Flea and drummer Chad Smith do all of the heavy lifting, but extended grooves don't make up for uninspired writing and generic radio-rock riffs (courtesy of new guitarist Josh Klinghoffer). Coasting on the rhythm section, Kiedis resorts to old tricks, rapping like it's 1994 ("Factory of Faith"), name-dropping California and/or L.A., and delivering groan-worthy lines like "I like you cheeky / Oh so Mozambique-y" ("Did I Let You Know"). Short on new ideas, I'm With You sounds like a band retreating to its (Hanes) comfort zone.