Ugh, you had to answer a tough question, didn't you? :-P
Spring '77 is definitely up there, especially early May at Barton Hall. Also really enjoy 1983, Brent really started to come into his own & inject his own flavor to the mix. Pretty much any tour in '74, the Wall-of-Sound really adds a dimension that's quite unique.
I'd have to agree on 83, the more I listen to the Brent years, the more they become my favorite. I love Pig and Keith, but what Brent brought to the band really lit a fire in Jerry. Those two could really play off of each other so well.