Here is one you may have forgotten.
During the 1999-00 season the Pittsburgh Penguins and Washington Capitals rivalry was really starting to hit its stride. The two teams had already met in the playoffs five times over the previous decade (with the Penguins winning four of those series, three times overcoming significant deficits in the series) and were set to meet again for a sixth time.
The Capitals finished the season with the better record (14 points ahead) with the third-best record in the Eastern Conference.
That, of course, gave them home-ice advantage in the series.