I would say Kanye and Just Blaze where the greatest sample-based producers in the 2000's. They where so innovative back than.
Kanye lost his mind on the new stuff though.
Pete Rock & Premier in the 90's though.
Lets see Madlib, Amon Tobin and I have to add Dday One to the list people sleep on this dude, if you dont know who he is, do yourself a favor and Google the name you wont regret it.
Damu The Fudgemunk's definetly my favorite. DJ Premier, Pete Rock, Easy Mo Bee, Q-Tip, Kanye are all classic. Gotta have Madlib and J Dilla on here too.