Hot/cold streak: I was gonna say Kenneth Branagh 1989-1996, because of Henry V, Peter's Friends, Much Ado About Nothing, In the Bleak Midwinter, and Hamlet, but then I realized Frankenstein and Dead Like Me are in there. In any case, he's had an ice cold streak post-Hamlet.
Hot hot streak: Michael Ritchie, 1972-1976 (Prime Cut, The Candidate, Smile, The Bad News Bears). Already discussed in the Movies... thread. I've now seen The Bad News Bears, it's every bit as good as people say, and thus it extends the hot streak even further. Still haven't seen Downhill Racer (1969), which preceeded Prime Cut, but I have a copy coming my way soon.