I'm kicking myself for not thinking of this earlier:
Hot streak--Elvis Costello 1977-1982
Cold streak--mostly everything else, with a good year here and there (1986, for example, was "King of America" and "Blood and Chocolate," two great albums; 1994 for "Brutal Youth" and "Kojak Variety.")
You could argue that his unwillingness to release the same kind of stuff over and over again is commendable (it is), but I don't think the quality is there. Also, he's pricing himself out of having a younger fanbase, annoying everyone with the constant re-releases in different packaging, etc.