Adam "MCA" Yauch is still our favorite Beastie Boy.
Tracing the influence of King Adrock and Mike D in terms of vocals is pretty easy. Rappers from Eminem to MC Paul Barman and beyond employ the nasal delivery of those two. And Adrock especially, whose punkish, puckish delivery defines the Beastie Boys for most listeners, despite Mike D's deadpan delivery of hilarious lines.
But few emulate or approach MCA's dry howl. Even as he's helping create a false origin story for the band in "Paul Revere" his voice has a the crispness of an elder statesman. He could get at both the winking comedy of early career Beasties -- drawling as if he'd been up all night pounding brewskis and bumming smokes from your girlfriend -- and the conscious rapping/positivity of the trio's later material.
He's gone, it sucks, and he'll be missed. We're not sure how long this eulogy will be up on the landing page of the Beastie Boys site, but you should read it. That's how you spend major label money and influence.