With Jay-Z’s recent retirement, the Roc-A-Fella dynasty seems to be crumbling — Memphis Bleek’s December release flopped, and Beanie Sigel is embroiled in legal troubles. Enter unlikely savior Kanye West, a 26-year-old MC with a clunky flow and an off-key warble that rivals Biz Markie’s tone-deaf crooning. West is better known as a producer than a rhymer — his beats for Jay-Z turned dusty soul grooves into slick modern funk — but his surprising debut disc, College Dropout, is the most impressive hip-hop CD of the young year. What’s his secret? For one: lush, intricate, and unabashedly pop productions that are alternately uplifting (”Jesus Walks”) and jiggle-inducing (”Workout Plan”). More important, the Chicago native shuns hip-hop’s tired ”Scarface” iconography for a broad topicality — family drama, everyday racism, crappy day jobs, and chasing tail all get equal time. This appreciation of life’s minutiae can go too far: The autobiographical ”Through the Wire” is hip-hop’s first, and hopefully last, song about a broken jaw. But West delivers the goods with a disarming mix of confessional honesty and sarcastic humor, earnest idealism and big-pimping materialism. In a scene still dominated by authenticity battles and gangsta posturing, he’s a middle-class, politically conscious, post-thug, bourgeois rapper — and that’s nothing to be ashamed of.