Calling All Phish Fans

Can anyone help me to learn more about Phish?

While wandering through a record store recently, I was really grabbed by the music playing in the background -- and surprised to find out from the store "DJ" that he was playing Phish -- something from a double album perhaps?

It has now faded from my memory a bit, but I thought it sounded get up out of my chair catchy and rythmic and layered -- less stonerish and Grateful Dead esque than I would have expected. (Not that I have anything against either of those subjects.)

To further pique my interest, a friend of mine (although he is not an audiophile) recently told me that he thought the best demo for a great stereo system was anything by Phish?!?!

Does anyone else agree that Phish is a good audiophile demo?
And where should I begin? Is there a classic Phish track or CD that will quickly get me up the learning curve? Are any better recordings than the others?

Thank you very much.