I've been going to shows since 1980 (I was 15 - you do the math) and I have seen upwards of 400 at this point. Could not possibly pick a "best" but a few stand out in my addled memory.....
Pearl Jam on the "Ten" tour at Jannus Landing in St. Pete
www.jannuslanding.net
CSN at Candlestick in San Fran 1984
Ziggy Marley at Embarcadero in San Diego 1994
Rainbow (Ritchie Blackmore smoked!!) at Lakeland Civic Center in 1982
there are many more - I have two shoeboxes full of stubs......