I Think It May be Super Brooklyn by Cocoa Brovaz
Duuuuude.
Welcome to the Boards! 
[Moderator Hat ON]
Moving to Cafe Society.
[Moderator Hat OFF]
Gangster’s Paradise. I know, it’s really Stevie Wonder but my god, that song has a hook that could land a blue whale, it’s so fat.
Cartooniverse
Welcome to The Boards, too !!
I’m both old and old school, so:
The Haunted House of Rock - Whodini
White Lines - Grandmaster Flash
Planet Rock - Afrika Bambaataa and Soul Sonic Force
It was a Good Day - Ice Cube (for those mellow rap fans)
Men in Black - Will Smith (I think I only like this one since it’s actually just rap on top of Patrice Rushen’s “Forget Me Nots”)
Joy and Pain - Rob Base (once again, helped greatly by the original, Frankie Beverly and Maze version).
I’ll also second Cartooniverse’s choice and throw in Snoop Dogg’s “Nothin’ but a G-thang.”
But, the best rap beat I’ve ever heard are by a white British lady who doesn’t consider her work rap at all. It’s music, and she’s talking, not singing, so too bad. 
That is Anne Clark’s “Sleeper in Metropolis.”
Dr. Dre is widely considered the best rap producer of all time and one of the best music producers of all-time period. At least a few of his beats would have to be on any kind of list. Timbaland also makes some pretty amazing beats.
Woo Ha (I got you all in check) - Busta Rhymes
Bedtime Story - Slick Rick
Let your Backbone Slide - Maestro Fresh Wes
Root Down - Beastie Boys
Go download them if you haven’t heard them.
Um, isn’t it Kenny Rogers?
New And Improved nailed it. Root Down is it without a doubt.
None of the above is a beat. They are all songs.
There is however an easy answer.
The greatest hip-hop beat ever is the sample from “Give the Drummer Some” by James Brown, as used by Public Enemy, and then just about everybody else.
I don’t think there can really be any argument.
Honorable mentions go to “Lyrical Gangbang” by Dr. Dre, which sampled “when the levee breaks” by Led Zep and anything based on a P-Funk break, so basically the entire Digital Underground / Redman back catalogue plus a large amount of Snoop dog, Dr Dre, Ice Cube, etc.
Didn’t the Beastie Boys and/or Rick Rubin do this first (on Licensed to Ill’s “Rhymin and Stealin”, released in 1986)?
It is a pretty cool beat though.
How about Run-DMc’s beat in Walk This Way? Not the best, but it’s a solid contender.
Bow wow wow yippie yo yippie ye - Snoop Doggs in the muthafuckin houuuuse
I’d have to say Digable Planet’s Rebirth of Slick or Pharcyde’s Passing Me By.
Schooly-Mother-Fuckin’ D (later sampled by Biggie on “Life after Death” - 'B is for the bitches. . . ').
People always ask me what the hell does that mean . . .
DaLovin’ Dj
Not being a huge fan of rap, I can say that “Gin & Juice” by Snoop Dogg, and “Can I Get A…?” by Jay-Z caught my attention.
Of course “California Love” Tupac was smooth too. However, as someone pointed out, 2 of my 3 choices are produced by Dr. Dre, so I suppose you would look at his beats, and go from there.
EPMD “So what you sayin”
Public Enemy “Rebel without a pause”
Run DMC “King of rock”
Eric B and Rakim “Know the Ledge”
Gangstarr “Take it personal”
Jeru “Come Clean”
Whodini “Funky Beat”
How about James Brown’s “Funky drummer”, because thats where half the beats in Hip-Hop originally were derived from.
“Funky Drummer” is indeed the best beat. I think that’s what longjohn was referring to with that “give the drummer some” remark.
The best song? “Cold Lampin” by P.E.
I think longjohn and World Eater have nailed it.
Jack Dangers of Meat Beat Manifesto conjures up some amazing drum loops that always leave me scratching my head.
How about the best beat that I’ve never heard sampled?
Steve Gadd in “Fifty Ways to Leave Your Lover”. Good lord, tell me someone’s used that, it’s just…just…SICK! (Throws sticks in the air, runs away)
The Best RAP/HIP HOP beat?
Beastie Boys - So Whatcha Want
arrrgggghhhh awesome!!!