lately, I been diggin Just Blaze and MF Doom. I'm not big into Dooms rhymes but I like his production style. Of all time? I can't name one. Did anyone mention Large Professor? How bout Diamond D? Showbiz? Q-Tip?
Suffa - just because his beats have a way of pulling me into the track, be it getting me hyped up, emotionally, or just generally proud of the australia scene
J. Dee: he was very skilled at making samples evocative. He'd also use human voice as an instrument in very interesting ways (listen to Talib Kweli's "Stand to the Side".)
DJ Premier: We both have the same creative process for beats (obviously I pale in comparison to even his worst material [which is better than most people's best].) We hear a song in our minds and then search for the sample that fits it best.
Also, Premo's production is the MOST street; 'nuff said. Nobody can match his beats. They all have that AMAZING feel that only he brings across. I think it's most evident in Nas' "I Gave You Power"