As of right now, the Montreal Canadiens can face any of four different teams in the first round of the playoffs, all determined by the last game of the season for a few teams. Let's quickly break down each possible opponent's pros and cons, then you can vote on your preference.
Probability: 38.8% according to Sports Club Stats
Season series: 1-1-1
Pros: The Penguins are limping into the playoffs, with just three wins in their last 13 games, and have gone .500 for the last half of the season or so. They're missing Kris Letang for the remainder of the year, and with Christian Ehrhoff, Olli Maatta, and Derek Pouliot also out, their defense core is a shell of what it could be. Marc-Andre Fleury in the playoffs is always a factor worth considering.
Cons: On the year, the Penguins have the fourth best score-adjusted possession in the Eastern Conference, and since February 1st, they're the second best. Sidney Crosby and Evgeni Malkin are a one-two punch down the middle that the Canadiens can not match. The Penguins have one of the lowest shooting percentages in the NHL the last couple months, and that's bound to regress sooner than later.
Probability: 37.3% according to Sports Club Stats
Season series: 1-3-0
Pros: It gives the Canadiens an opportunity to get back at Ottawa for handing the Canadiens a playoff loss in 2013. Andrew Hammond is playing far above his station and is bound to fall back down to earth. The Sens have been extraordinarily lucky on their run up to the playoffs, and could face regression as the playoffs begin, combined with the mental exhaustion of playing "playoff hockey" the last two months.
Cons: The Senators are have been legitimately great under David Cameron, they're the fifth best score-adjusted possession team in the East since the New year. The Senators have had the Habs' numbers this year, the last few games haven't even been close. Regression doesn't always happen when you want it to, we saw that in 2013.
Detroit Red Wings
Probability: 20.3% according to Sports Club Stats
Season series: 4-0-0
Pros: The Canadiens have won every game against the Red Wings this season, even one without Max Pacioretty, and another with Dustin Tokarski starting. Pavel Datsyuk and Henrik Zetterberg both have continual health problems, meaning they're unlikely 100% in the playoffs. Detroit's goaltending is suspect to say the least. Outside of Nicklas Kronwall, Detroit's blueline is a rag tag group of third pairing guys.
Cons: Michel Therrien going head-to-head with Mike Babcock over a seven game series sounds terrifying. Detroit is the second best score-adjusted possession team in the Eastern Conference since the new year, and have the second best powerplay in the NHL. Last year Detroit's young guns were playoff newbies, this year is very different.
Probability: 3.6% according to Sports Club Stats
Season series: 4-0-0
Pros: The Canadiens have a mental edge over the Bruins that can't be quantified, it's just always there. Tuukka Rask is terrible against the Habs. The Bruins don't have nearly the scoring punch they used to, and they're not as good defensively either, yet they haven't gotten any faster. It's always the most fun series in the playoffs when these two teams play. Dougie Hamilton could miss the first round, which leaves the Bruins very shorthanded defensively.
Cons: Series against the Bruins always go long, no matter how good or bad the Bruins are, and they take a physical toll. The Canadiens haven't won a series after being the Bruins in years, it just seems to take too much out of them. In spite of being older, and less potent, the Bruins are still a legitimately good team. They're not great, but they have much better possession numbers than the Habs, and are due for some victories in the rivalry.