Lupe Fiasco, who grew up on Chicago's rough west side, came out the gate performing Fabolous-style street rap (over Chicago house samples, no less!) but it wasn't until the series of Fahrenheit 1/15 mixtapes dropped that the rapper seemed to find himself, bringing Kanye's conflicted neuroses and wedding them to a dexterous technical skill.

The best of these tapes was Part II, subtitled Revenge of the Nerds, from the meta-rap verse of "Mean & Vicious" ("Truthfully, I have trouble with second verses/'cause the first one be so intimidating, it be bullying, instigating/pointing out all the second one's limitations") to "Switch (The Science Project)," arguably the most incredible moment of his technical prowess.

For those unconvinced of Lupe's abilities, "Switch" found the rapper rotating through a series of flows in a deft double-time over the "Still Tippin'" instrumental, an electrifying exemplar of devotion to craft. He remained rooted in Chicago past—witness the effortless double-time that closes his Crucial Conflict reinvention "Don't Get It Twisted"—while thinking of the future, introducing the artist who was to be his protege, the underrated Gemini.

But the strongest sign of the rapper's emerging personality came near the end of the tape, when Lupe took to Kanye's "Diamonds" instrumental, spreading awareness about the history and origins of hip-hop's "bling, the crystal-encrusted princess-flooded canary studded blue colored and blood-stained." —David Drake