Bob Dylan
The Rolling Stones
Stevie Wonder
The Beach Boys

And tied with Jackson, Aretha, Ray, Zepp. 

I agree with those except for Dylan and the Stones.
But most of them are so dangerously close that there's no way to make a decision.

I'd be interested to hear from Sampson what Berry's cultural impact is...

I think the same.


Cultural Impact or Musical?

Cultural. I'm sure he could explain it much better than I.

Berry's influence is indescribably profound as well.

Top 5, easy.

I would've thought those would be the other two ahead of him.

In musical impact? Well it's dangerously close, but I dont think so really...

My take on musical impact:

1st tier: Beatles, Elvis, Dylan
2nd tier: Rolling Stones, Ray Charles, Stevie Wonder
3rd tier: James Brown & Aretha Franklin

So I think at least those 8 beat Berry in musical impact, and probably also The Beach Boys. But probably not Michael Jackson or Zep.

I think there are twelve leading artists in this criteria.

My take:

1st tier: The Beatles, Elvis Presley
2nd tier: The Rolling Stones, Bob Dylan, Stevie Wonder
3nd tier: James Brown, Ray Charles, The Beach Boys, Michael Jackson, Aretha Franklin
4nd tier: Chuck Berry & Led Zeppelin.

Actually Brian I agree with that.
The only thing I disagree with is James Brown being 3rd tier. He's 2nd tier at the very least. Come on. This is the Godfather we're talking about! Enormous praise throught hip hop, r&b, and most of 'classic rock' in general.
And even blues artists like B.B. himself have sang the praises of Brown.

That's true. The Stones can't be above JB here. They shit their pants when they had to follow him on the TAMI show in 1964.

To be fair though, that's kind of overstated.
The Stones were still very embryonic in 1964, they hadn't yet developed into the monstrous live band they would become by 1969.

But yes, JB > Stones for musical impact, but then I dont think James could ever budge from #3 so I guess it doesn't matter really.

Oh, come on. Led Zeppelin do not beat The Who in musical impact. Especially since it's defined primarily as reaction to your work soon after its release.

Yes, they do.

No, they do not. Nothing in Led Zeppelin's repertoire had the impact of "My Generation", Tommy or Live At Leeds. Arguably not even the impact of Who's Next or Quadrophenia. The Who's praise is beyond Led Zeppelin's.

Led Zeppelin were also as reviled as they were praised in their day: "Just looking at their album covers makes me want to throw up." - Paul Simonon

Even today you have opinions like this: "Fuck off, Zeppelin, you're crap. You've always been crap and you'll never be anything else." - Jack Bruce

But here's John Lennon talking about Yoko Ono:

"I’m digressing from mine, but if somebody with a rock-oriented mind could possibly hear her stuff, you’ll see what she’s doing. It’s fantastic, you know. It’s as important as anything we ever did, and it is as important as anything the Stones or Townshend ever did." link

That shows you what enormously high regard John Lennon held The Who in. When trying to come up with the most important work in rock, he's got an awfully short list. I think it would have been a long time before he got to Led Zeppelin.