Y’all seem to have mentioned all the good ones, but I wanna chime in anyways, just because I’m freaking out so hard about Saturday, that I need to “blow off some fucking steam”, to quote Trey.
I remember the PIPER from MSG NYE 02. The crowd was so loud you couldn’t tell what they were playing right away. Hampton is going to be twice as loud.
Whatever they start off with, it will be something that they won’t mind us screaming beserkly over for the first minute or two. So it’ll be something with a nice extended intro.
Not YEM. That will be second. 
I’ve been thinkin about what fits the criteria, and there’s a bunch that could work and knock our socks off right away.
First and foremost, Also Sprach Zarathustra, good ole 2001.
Those lights. The way it hits the peak and BLAM!!! there is PHISH bathed in the white spotlights - the absolute FIERCE.
Kill the house lights, fill the stage with smoke, have them lead onstage with flashlights (no one sees then until the peak), they make trippy noise, and then Fishman slams into the beat and all hell breaks loose.
I guarantee brains will EXPLODE if they do that.
Down with Disease is also one of those “come out and make a lot of noise first” songs and they love that song, and know we love that song and that JAM ever since NYE 93. But the more I think about it, DWD is more likely to be the second set opener on Friday rather than the first set opener.
For an unlikely choice, I really agreed with Mr.Miner’s Phish Thoughts blog where he suggested UNDERMIND. Lyrically, it fits beautifully, and it’s a song they could just groove on while everyone wigged out for a few minutes before settling into. It reminded me of when we tried to predict the Millenium song. MEATSTICK was the absolute LAST song on my mind for that, and the way they did it with the hotdog was priceless.
I would like to see them make up for the disaster of the CURTAIN WITH, but its a song that I think they’ll wanna make sure we’re all listening instead of shouting our brains out when they play.
They could also slam into it with such classics as Chalkdust or Llama.
But I know them, and whatever it is they do, it will be carefully thought out.
Each song for each night will be selected and well rehearsed. I’ll bet that they already have a song list and are practicing on their own free time to get ready for rehearsals after the new year. They know very well what happened at Coventry and these Hampton shows are gonna be the “make-up” shows. And that means say goodbye to the roof of the Mothership, because within minutes of them taking the stage, it will be gone.