For John Scofield a good place to start might be A Go Go. A cd he did with Mediski, Martin and Wood. It's a jam based album with some excellent tunes. Other favs are Hand Jive and Up All Night. Scofield albums are like a box of chocolate - you never know what you're going to get.

It's always something worth listening though.
My favoirte Phish cd is Picture of Nectar. The album is all over the place from a style perspective with hints of blues, bluegrass, country, jazz and really shows the diversity of the band and it has my all time favorite phish song - Chalk Dust Torture. No phish exploration is complete without at least one live cd and they have a bunch of them. I'd recommend Live Phish, Vol. 7 as one of the better ones.
Old Yes, get these three - The Yes Album, Fragile and Close to the Edge. All are excellent.
Galatic is an excellent band and I think just about all their recorded material is worth a listen. I especially like Coolin' Off and Ruckus.
Medeski, Martin & Wood are great. My recommendation would be Combustication and Party at the End of the World.
Another band you might like to sample is The Word. This was project combining the North Mississippi Allstars, John Medeski and Robert Randolph into a jam rock supergroup. They have one cd called The Word. It's all instrumental and the jumping off point for their jams are gospel songs. Randolph is clearly the star but the supporting cast is excellent. I think you might like it.