Nishat Khan would have to be one of the many Khans assumedly of the etawah gharana...I know Vilayat, of course, and Imray, Inayat, Rais, etc. Plenty of Khans! (looks up) Appears to be Imrat Khan's son...Imrat Khan is the master of the surbahar alaap from my modest listening experience. Zakir Hussein of course needs no introduction! I like the jugalbandi he did with his father, there are some excellent recordings.
I know there are many who think that Ravi Shankar was a sell out and totally overhyped...but the more I listen to him, and then the musicians commonly posited as superior (Vilayat Khan, other Khans, Nikhil Banerjee) I keep coming back to Raviji. I like them all, but if I have to be a partisan (and from dealing with sitar playing circles, its almost like you have to be! lol) I love Ravi's playing most of all. I've heard his style ascribed to his early background when he studied dance. Vilayat Khan developed a "singing" style of sitar, Ravi Shankar's playing was almost like a dance.