QB's Finest remembers well when he first heard himself spit, "Street's disciple, my raps are trifle/I shoot slugs from my brain just like a rifle."

He was in his old neighborhood late at night, and he heard the radio playing from a car on the corner. Some older guys were standing around, "doing their thing, talking and kicking it," Nas recalled.

"As I'm walking by, 'Live at the Barbeque' comes on, and I'm like 'Ohhh!' And I stopped, and I was like, 'Wow, this can't be real. This can't be real. This is me,'" he said. "I'm trying to let them know that's me. And they're kind of like, 'Cool,' and go back to their conversation. But it didn't matter. I was so caught up to hear myself on the radio for the first time; I was in heaven."

That was the summer of 1991. Nas was 17. By contrast, Kendrick Lamar, one of hip-hop's hottest new artists, had just turned 4.

There may be 21 years between his first 26 bars on wax and his latest LP, but that doesn't mean "Life is Good" is geriatric rap, even if Spin magazine prescribed it "for the 40-and-over crowd." Nas said he was "humbled" by the review, though his shows seem to be packed with 20-somethings.

"It's important for me to give an honest opinion on the way the world has changed. I feel like it's just who I am today," he said. "To answer your earlier question, why I'm still around, it's because honesty is the best policy. 'The truth shall set you free,' in the words of the great Aunt Esther from 'Sanford and Son.' ... And I think that's where Spin is wrong. It's not for 40-year-olds. It's just for people who know what's up" (One more disclaimer: The author didn't ask, "Why are you still around?" in a snarky way.)

Which brings us back to the debate. Nas' 40th birthday in September will put him in the company of elite survivors, though only a few of hip-hop's quadragenarians can legitimately challenge him for title of best lyricist.

You've got DJ Quik, Sean Price, Tech N9ne and Doom -- all talented rhymers, but no Nases. There's also Common, E-40, Ice Cube, Busta Rhymes, Scarface, Slick Rick and Q-Tip -- again, a poetic bunch who've been in the game for more than a minute -- but none is Nas.

Big Daddy Kane, Rakim and Kool G Rap, all 44, were game changers, trailblazers even, but their catalogs get thinner the deeper you move into the '90s. Ghostface Killah and Raekwon made their marks on hip-hop and still do today, but they enjoyed more successes as members of the Wu-Tang Clan.

In fact, despite the well-warranted accolades heaped upon these five, there's only one platinum plaque among them: Ghost's "Ironman." (The forever-dope "Paid in Full" doesn't count. Sorry, solo efforts only.)

Dr. Dre, 47, and Snoop Dogg, 41, have long enjoyed broad appeal, from college campuses to Compton corners, but neither is known for the complexity of his content or rhyme schemes. Their production is always extraordinary, and they know how to make heads nod, but lyrically? It's more fun than prophetic.

'Exercise till the microphone dies'

Which brings us to the top five, the professors emeritus. Out of respect for Nas' aversion to lists, let's handle them in no particular order.

Eminem is a beast. As Nas points out, the list will be different in 10 years, and Slim Shady may be atop it, but in 2013 you can't challenge Nas if you dropped your first LP in 1999.

Then there's Pac and Biggie -- and the point where the debate might venture into hurting someone's feelings.

Makaveli dropped six albums, four of them platinum, between 1991 and 1996 before he was gunned down in Las Vegas. The Notorious B.I.G. put out his first record in 1994 and was slain in Los Angeles weeks before his second release, "Life After Death," in 1997.

Both have successful releases after their killings, but their life spans, tragically, were too brief, and for that reason -- and that reason only -- it's unfair to put them up against a man with two decades in the game.

Nas still believes Pac and Biggie are "two of the greatest who've ever done it," and it's not because they died. Big L died. Guru died. Big Pun, Eazy-E and Ol' Dirty Bastard died, but they didn't leave the same legacy.

"I just think Biggie was something else. He was the Hitchcock of this thing, man. He told you a story. There was a seriousness that came with it that can't compare with nothing," Nas said.

He wishes the pair hadn't been taken in their mid-20s, he said, because they "would be at the top of the game" today, and they would've pushed him.

"I'd probably be better if they were still around," he said. "I think I'd be a lot better."

"To leave us with that kind of music at that young age is exceptional. There's no other word to say," he said. "They were bigger than all of us, even today -- their music, their sound, their topics. The way the world listened to them was a lot bigger than I would even say myself and the rest of us ... I don't think today we've made an official impact that those guys were just starting to make."

Watch the throne

... And then there was one: Jay-Z, a man who spent the the late 1990s and early 2000s also pushing Nas, and his buttons, during their quest to rock Biggie Smalls' "King of New York" crown.

Let's not bother with the details of their long-snuffed beef or who said what about whom on what album (though, let's face it, Nas' Ginsu verses on "Ether" made Jay's "Takeover" and "Super Ugly" sound a little nanny-nanny-boo-boo. Jigga himself called "Ether" an inescapable "figure-four leg lock").