thats a hard one...all 4 are good, but lets see...

Dr. Dre-Real West Coast G-Funk type shit
The Neptunes-Experiment With Alot Of Different Instruments
Just Blaze-Samples Alot Of Soul, Good Club Type Beats
Swizz Beats-Some Strange Shit, Makes Tight Beats Too

On This One, I am Going To Have To Go With...The Good Doctor...D.R.E.