Honestly, none of them. I'm not too into multiplayer anymore, I'm more of a co-op type fan. If Star Wars Battlefront had a good campaign mode, I would have probably jumped on it. As it is, my normal rule of 'if a close friend or two picks up multiplayer game X and wants me to play with them I will' is in effect for these titles.
Halo 5: Guardians has given players little reason to be excited. 343i did a terrible job with Halo 4's multiplayer, and the campaign - while it had some very good things - overall was a disappointment. Even though I don't blame them entirely for the MCC debacle, between Halo 1 Anniversary, Halo 4, and the MCC they have struck out three times. Unless they actually figure out the fundamental qualities that made Halo so special and relatively unique, I have little faith in them.
I think Battlefield and Call of Duty will be about what people expect from those two games. That could be a bad thing, as people might just be worn out on the same games, or it might mean a large percentage of the audience is relatively happy. Of course either game could show up at E3 with some exciting ideas. I hope they do.
Star Wars Battlefront is such a difficult call. It has no campaign, which would have made a lot of people more inclined to get the game just out of fandom (such as myself). But, if there is a studio that I think has the capability to make it work, it's Dice. Battlefield excels at large scale, varied combat and beautiful visuals. They have the entire sound catalog of Lucas Studios and already have a stellar reputation for sound design. Many of the pieces are there, but something in the back of my mind is telling me it will be one of those games that are decent but hugely disappointing because its not the game the fans expected. And, like I've said, a campaign could have offset that some. Hopefully by focusing on multiplayer they can deliver a fantastic game with enough modes and options to warrant the price tag.
