Aja is an excellent suggestion. I personally love The Dan as much as Phish, and would choose The Royal Scam In fact, the band regularly does extended night runs at the Beacon Theater in NYC where each night thy play one of their albums in its entirety, then a bunch of "greatest hits" songs. We attended 10/3 this year because it was "Royal Scam Night".

But, Aja is the album that more people are familiar with. And thus, it would be more of a crowd-pleaser for Phish. I would be ecstatic! The title track is probably my favorite single song of their's. Can you imagine Fishman doing that famous Steve Gadd drum break? (BTW, SD also performed that tune when we attended on 10/3. Incredible.)

@listentomorejazz said:

Steely Dan's Aja.

It has the technical proficiency to keep them interested, and there is room to jam on that entire album, especially if they bring in the needed horns. Plus, hearing Mike hit Michael McDonald's high notes in Peg would send most people over the top.