Only seven teams have won back-to-back Stanley Cups. This list includes the Montreal Canadiens, Detroit Red Wings, Toronto Maple Leafs, Philadelphia Flyers, New York Islanders, Edmonton Oilers and most recently the Pittsburgh Penguins. That would suggest it's a bit of a longshot that any team will repeat as a Stanley Cup champion.
However, of the 20 teams that have won a Stanley Cup, 13 have won more than one, and only seven just one. That makes it a good bet that the team that win the next Stanley Cup will have won a Stanley Cup previously.