Ugh...probably not Halak. He's been absolutely terrible in his last two games against Minnesota this season.
Price has been average against the Capitals in his career but he's had two good games against them this season, and they'll be playing at home where he's been amazing.
Varlamov has been amazing this season against the Habs.
At this point I might go with Price vs. Varlamov assuming that he's starting. Seems stupid but it might turn out to be a low scoring game with both teams focusing on defense.
These teams have played each other 3 times, twice with Varlamov and Price squaring off, both those games were 3-0 win for WAS (1 EN goal) and the other one was 3-2 SO win for Price.