When you are at a loss of words, it’s pretty indicative as to the quality of the show/set/song/jam/riff/etc. I mention riff too because there have been plenty of times where one of the boys drop “the” riff and you are just like wow. Then everyone else starts picking up on it and you begin to feel that indescribable build within. I don’t think Webster has a noun or adjective that accurately describes that feeling.
Crunchy, hetty, granola space funk are all great though.
Big Fat Oprah Titties
I’m a big fan of “ridiculous”, “epic”, “sick”, “out of control” and the standard “awesome”
Another favorite response is just “dude…”
I’m speechless
Sick
Crazy
Nasty
Dirty
Scary
Trippy
and usually immediately following a show I am so overwhelmed that i tend to come to this conclusion-
Show of the Tour
by far the best way to express your feelings towards anything…
MOM this turkey is Big Fat Oprah Titties!
after I can find words they’re usually
nasty
killer
wicked 
^ Um . . .Barb?
I also tend to find my self saying “Uhhhhhh” (akin to Master P) while doing a tasteful pelvic thrust
Ahahahahahahaha! You ARE friends with Brett!!! 
“Yeah! Belt buckles are a great way to express yourself.” - Chris
PshhhFuck.
It really depends on what I’m trying to say… I try and suit my slang adjectives to the occasion, y’know.
But the generics include:
“off the hook”
“killer” (great minds, of course)
“immense”
“mindblowing”
“luscious” (if it’s funky)
“bootyriffic” (if it’s REALLY funky)
“saucy”
“uplifting”
“transcendent”
“angelic”
“trance-inducing”
“i have a boner” (er, wait… that’s not relevant here 
)
cari… it’s killer that we’re more alike than two people should be 
I probably say awesome about 90% of the time, but others include …one of the best I’ve ever seen, unbelievable, phenomenal, or the adverb adjective for effect; ridiculousy awesome, crazy good, etc.
this 
(<- not a “thumbs-guy”, a “pointing up” guy)
i refer to this as phish shock. (ie. man after portland i had the worst case of phish shock i’ve ever had)