I'd probably go with those circa 2000 Devils due to the fact that the same core group of players was together for several years performing at a high level.
Avalanche of 2001 playoffs was incredible, just as good as New Jersey, but that group only stayed intact for that single Cup run.
Chicago's core group of Keith, Seabrook, and Hjalmarsson has been together for two Cups now. I'd probably nominate their 2013 edition due to Hjalmarsson and Oduya both playing their best hockey to date during that playoff run.
Detroit and Dallas teams of the dead puck era deserve mention as well.
Thinking back on it, as much as people like to blame clutching and grabbing for lack of offense at the time, you have to acknowledge that all those Cup winners from 1995-2003 had exceptional bluelines and usually Hall of Fame goaltending to go along with it. No surprise that they were difficult to score on.
96 Coffey (well protected defensively on that team) Lidstrom, Kontantinov (at his peak), Fetisov much better in his role on this team made a great top 4 along with Bergevin (a great locker room guy)Ramsey and Rouse (in part time limited roles).
97 switch out Coffey for Larry Murphy for the playoff run basically but I think the 96 D group had better chemistry and mix back there.
Post lockout the 10 Black Hawks had a great mix on the back end versatile and just plain excellent as a group.
The current Bruins group looks really good, especially depth wise considering injuries to their 2 top guys, although Chara only missed 3 games.
And although they certainly don't belong in this group the 14 Flames back end is a lot better than the team overall that really lacks scoring and is having goaltending issues now that Kipper has retired.
As a group they (the D group) have really outperformed well beyond their expectations this year.
The 2007 Ducks were scary good with Pronger, Niedermayer, Beauchemin and O'Donnell as their top 4. Three of their top 4 averaged 30+ minutes of ice time during their Cup run, then the bottom 4 guys like Huskins, Rome, DiPenta and Jackman averaged between 12 to 6 mins. I guess the depth guys didn't matter when Pronger, Niedermayer and Beauchemin played half of 60 minutes.
with that bottom pair being two guys who were just veteran guys who knew how to get it done in the playoffs.
for star power, you'd go
but in terms of effectiveness, it's easily the '99 stars among the stars teams.
and a few great "on paper" d corps that were actually terrible teams but might have been good had they been kept together"
'00 canucks had ohlund, jovanovski, mccabe, and aucoin, and a bunch of spare parts that included a still-useful murray baron, a young brent sopel, jason strudwick, and dana murzyn's corpse.
'98 isles had a very raw chara, berard when he could still see, mccabe as their captain, kenny jonsson, scott lachance, richard "pilon" pilon, and the immortal jason strudwick again. they started the previous season with basically the same group except with kasparaitis instead of chara.