One of hip-hop’s greatest rivalries has yielded some yearned-for duets — most recently on DJ Khaled’s latest album. How do they all stack up? — 6. “I Do It for Hip-Hop,” Ludacris Featuring Jay-Z and Nas Despite solid, straightforward verses, this solemn Theater of the Mind deep cut is a bit ham-fisted — like pandering too hard to the kind of dudes who refused to acknowledge Soulja Boy as #realhiphop. Loosen up a little, fellas. Sheesh.