RED HOT CHILI PEPPERS Stadium Arcadium (4 Lp's)An ambitious double album, STADIUM ARCADIUM finds the Red Hot Chili Peppers building on their more mature, latter day approach, while also acknowledging their lighthearted, youthful sound. The Los Angeles based funk rock quartet's third studio outing since John Frusciante returned to the fold, this 2006 release once again reinforces how crucial the guitarist is to the Peppers' aesthetic, with his mix of swirling, psychedelic leads and heavy riffs