Tuzenbach said:
fun x 1 < fun x more-than-one
There are whole schools of moral philosophy that argue against this.
Personally, I voted "everyone equally." This is because I assumed initially that the poll meant to deal with absolutes, meaning that there are only two possible conditions: "having fun" and "not having fun." In that case, it's the highest priority that everyone be "having fun."
Now, the question becomes a bit more sticky if we assume that everyone is "having fun" but that certain individuals'
degree of fun may vary. In this case, I'd vote for the DM. The DM spends a lot more time thinking about the game, preparing for the game, and then runs the game, whereas a player need only think of the game while he is actually playing. Because of this, the DM needs to be excited about the campaign concept enough to sustain his interest in the long term.
If a player "likes" a campaign idea but doesn't love it, he'll still have a fair bit of fun in the game.
If a DM "likes" a campaign but doesn't love it, he's going to have a hard time brainstorming ideas for its long-term survival, being excited enough about it to put in the work statting monsters and creating dungeons, etc. etc.
So if if comes down to only one or the other being "excited" about the campaign idea, while the other merely "likes" it, my nod goes to the DM. Though of course the best possible scenario is where both DM and players are excited about a campaign.
