Here's my contribution to the discussion:
There's plenty of other artists that have pushed envelopes in hip-hop. Just 
because the Beasties put humor into it, or punk chic, or trippy 
stuff--whatever you want to call it--doesn't mean that their efforts will 
stand the test of time. I think the Beasties benefit from the folks that 
help them out with producing/finding sharp samples, etc., much more so than 
people are willing to readily admit. I also think the fact that the Beastie 
Boys are white have contributed to much of their fame, fortune, and 
critical acclaim. Sorry to bring it down to that, but in this case I think 
it's a matter of calling a spade a spade... Actually, maybe you're right, 
they are like the Beatles of the 80s and 90s...
gordon