Agree with Crease. Of course if the question is Pittsburgh vs. the other 15 playoff teams you have to go with the other teams being more likely, but as far as a single team goes the Pens are the most likely IMO. There's just such a ridiculous amount of talent, the only real question mark is goaltending but Fleury's been having a pretty good year, and as much as Vokoun's struggled he's still a legit goalie only a couple years removed from being top 5 in the league.
Depends on if they get "Phillied" in the early rounds, in other words a team just taking runs at them nonstop and getting them into a physical trench war instead of their passing/transition game. Since it looks like they'll face Rangers or Toronto round 1...yeah, I can see them getting another cup.
Even when a team is a CLEAR cut best team in the league... They still probably only have a ~30% chance to win. No matter how good you are, there's always a chance of being derailed by injuries, poor goaltending (hi Fleury), running up against a hot goalie (hi Halak)... You have to be elite and lucky to win the cup. There are no guarantees.