see, what i don't understand is why people can say that people like dennis chambers are masters of the groove. you almost never see him just straight groove. that is just my opinion. i still think he is an amazing drummer but i think of him as more of a chops drummer... 
Correction. People only pay attention to his chops. Even when he is playing a song that is stretching out he is always grooving. He establishe the groove so strong in the onset that it underies evertything. That i s why people like to play with him.
Dennis was also the house drummer for Sugarhill records ths foundation of hip-hop. And let's not forget the Parliament Funkadelic, which he joined at 17 years old. Though he state it took him like 3 years to understand the George Clinton definition of "pocket".
Groove is not necessarily straight that is a misconception and fals-teaching. Fusion has groove (as well as do other genre's of music). Mahavishu Orchestra inner mounting flame has some of the strongest groove you'll ever hear. You just have to know what you are listening to. That is what makes Dennis and Billy Cobham, Vinnie and Virgil Donati so dangerous. They can find the groove in what ever they play.