Outkast: When Andre 3000's eccentricities are paired with Big Boi's street smarts, the results are electric: 1998's "Aquemini" was an weird, wild masterpiece, while 2000's "Stankonia" gave the duo its first major hit, the still-classic "Ms. Jackson." Choice Cut: "Rosa Parks"

Dr. Dre and Snoop Dogg: Aside from creating "Nuthin' but a 'G' Thang," one of the best hip-hop songs ever, the West Coast hip-hop titans exhibited the kind of lyrical chemistry in the 90s that most hip-hop duos dream of, from Snoop's "Doggystyle" album to Dre's "Still D.R.E." single. Choice Cut: "Nuthin' but a 'G' Thang"

Lil Wayne and Birdman: Lil Wayne remains closely tied to Birdman the co-founder of Cash Money Records and a former member of Big Tymers. Between "Carter"s II and III, Weezy released "Like Father, Like Son," a collaborative album that also Birdman shine. Choice Cut: "Stuntin' Like My Daddy"

Jay-Z and Kanye West: Kanye West established himself as an all-star producer for Jay-Z with tracks like "Izzo (H.O.V.A.)" and "Lucifer" before becoming a star on the microphone himself. Their joint album, "Watch The Throne" is expected to sell over half a million copies in its first week. Choice Cut: "Otis"

Chuck D and Flava Flav: The artistic style of these two rappers couldn't have been more different -- Chuck stayed serious and socially conscious, while FLAAAAVAAA FLAAAAV remained hilarious and outlandish -- but as the leaders of Public Enemy, their dynamic was effortless and groundbreaking. Choice Cut: "Don't Believe the Hype"

UGK: Bun B and Pimp C were representing Texas long before Southern hip-hop reached the mainstream, but their first No. 1 album, "Underground Kingz," was sadly followed by Pimp C's death in 2007. Bun continues to release critically lauded albums as a solo artist. Choice Cut: "International Player's Anthem (I Choose You)"

Puff Daddy & Notorious B.I.G.: Sean Combs and Christopher Wallace's friendship helped establish Bad Boy Records and change the complexion of East Coast hip-hop. Following the Notorious B.I.G.'s death, Puff Daddy released his debut album, "No Way Out," which featured Biggie on several hit tracks. Choice Cut: "Been Around the World"

Ghostface Killah and Raekwon: While Ghost and Rae are both members of the Wu-Tang Clan, their kinship and creative output has thrived while the Clan has been in flux. Raekwon's great "Only Built 4 Cuban Linx" albums even feature Ghostface as a "guest star" on their album covers. Choice Cut: "Criminology"

Pete Rock & CL Smooth: These mid-90s mainstays were just as influential to New York hip-hop as groups like A Tribe Called Quest and Mobb Deep, but offered a more philosophical perspective on their strongest tracks. Choice Cut: "They Reminisce Over You (T.R.O.Y.)"

8Ball & MJG: This longtime duo has been grinding out stellar Southern rap for nearly two decades -- while they never released a hit single on their own, their guest spot on Three 6 Mafia's "Stay Fly" introduced their brand of hardcore hip-hop to a much wider audience. Choice Cut: "Comin' Out Hard"

DJ Jazzy Jeff & the Fresh Prince: Back before Will Smith was getting 'jiggy' with anything, he and Philadelphia's DJ Jazzy Jeff were putting out timeless bubblegum rap that even parents could understand. Choice Cut: "Summertime"

Eric B. & Rakim: Rakim is largely considered one of the greatest rappers ever, but it's hard to imagine the New York MC achieving that status without Eric B.'s slick, sample-heavy production behind him. Choice Cut: "I Know You Got Soul"

Ying Yang Twins: Crunk rap found two of its biggest stars when the Atlanta-based Ying Yang Twins began releasing a string of hits following a guest spot on Lil Jon's "Get Low." "Salt Shaker," "Shake" and "Drop" remain surefire party-starters. Choice Cut: "Wait (The Whisper Song)"

Gang Starr: Guru and DJ Premier released consistent East Coast rap throughout the 90s and used jazz as a foundation for their forward-thinking hip-hop. Choice Cut: "Mass Appeal"

Clipse: With the Neptunes bestowing them with some of their hardest beats, the brothers Thornton and their brand of coke-rap rose to prominence in 2002 along with their hit single "Grindin'." Their 2006 album, "Hell Hath No Fury," is furious and fantastic. Choice Cut: "Trill"

Mobb Deep: Havoc and Prodigy offered a darker sound than their mid-90s contemporaries, with their 1995 album "The Infamous" still standing as a must-listen. Choice Cut: "Shook Ones Pt. II"

Black Star: Mos Def and Talib Kweli have found prolonged success as solo artists, but many hip-hop fans best know the MCs through their acclaimed 1998 collaborative album. Rumors of a sequel have long been lingering. Choice Cut: "Definition"

Gucci Mane & Waka Flocka Flame: 1017 Brick Squad rappers Gucci Mane and Waka Flocka Flame have been longtime collaborators, and finally decided to combine their Southern drawls on the just-released joint album, "Ferrari Boyz." Choice Cut: "She Be Puttin' On"

Eminem and Royce da 5'9": 12 years after Eminem and Royce da 5'9" linked up on "The Slim Shady LP" track "Bad Meets Evil," the Detroit MCs returned to the studio for "Hell: The Sequel," a full EP of tongue-twisting rhymes. The pair recently showcased the album at Bonnaroo and Lollapalooza. Choice Cut: "Fast Lane"