A.J. Burnett is a guy I can think of off the top of my head who would have a 90+ pitch (curveball) and a 75 or 80+ pitch (fastball) who is only a good-but-not-great pitcher because, at times, he doesn't work the edges of the strike zone and leaves good-looking pitches out over the middle and they still get hit hard.
Edwin Jackson also, especially earlier in his career seemed to have awesome stuff but would get hit hard.
Cliff Lee would be an example of a pitcher that doesn't have any great individual pitches but rarely serves up an easy one to drive. Greinke seems like a guy like this as well, although I haven't seen as much as him. His stuff seems good, but never as amazing as Lincecum or Verlander, etc.... but yet he's just as good or better than those guys.