I really hope with all my heart that Liverpool wins the league. It might sound odd coming from a Man United fan, and while there is rivalry between the clubs, I feel like Liverpool is the club that deserves the PL title the most this season. They've played the best football in the whole league, they have some incredible players, and a legend like Steven Gerrard. He is one of those few players who truly deserves a title, for everything he has done for his club. I really don't like Oil-City (for obvious reasons I guess), and while I like Mourinho as a manager, Chelsea has been pretty darn boring this season. I really hope Liverpool takes it, because they would benefit the most from winning the title. It would be a boost to the club, but clubs like City and Chelsea will invest good money no matter where they finish.
As for Arsenal, I guess we could all agree that history repeats itself. A lot of fans got incredibly excited after the first half of the season, but as soon as the big games started to arrive, results started to decline. I think the best action at this point would be to win the FA-Cup and get the 4th spot, Wenger SHOULD leave after this season, and maybe he will end his run with a title. Wenger has once again proven that he is not the right man for Arsenal anymore. He has a few good qualities, but he has a hard time motivating his team and getting them to play good football, and against the top teams, Arsenal usually have no chance at all. Several games this season (against Pool and Chelsea for example), the game has been over after 10-15 minutes. Good preparations there, Wenger. Right now I think Everton is favorites to take the 4th spot. Arsenal has a much easier schedule, but Everton has a really strong form. I think Arsenal will get it in the end though, and Everton shouldn't feel ashamed if they miss it. I think Martinez has done a brilliant job at Everton, and I would even love to see him at Man United.
As for Man United, I really don't even want to talk about it. The season has been bad, but the situation overall doesn't give any glimpses of hope. At this point I would gladly replace Moyes with just about anyone else from PL. For me it's not just about results, but Moyes just hasn't gotten anything to work. If you take Liverpool last year, at least they were playing really good football. You could tell they had something exciting going on, and that their "project" had a bright future. With Man United, the games have mostly been very boring to watch. I don't think someone like Klopp would leave Dortmund to come, but I'd even be thrilled over a manager like Martinez from Everton, or Pochettino from Southampton. Both those clubs play positive football, and they have done wonders with what they have.
Overall though, I would say that Tony Pulis deserves the "manager of the year" award this year IMO. When he took over Crystal Palace, they were dead last, with a pretty thin squad, and most people said "it's an impossible job". Now they are pretty much safe from going out, and they wouldn't have done it without Pulis as the manager. He may play a "simple" football, but what a good job he has done.