For bootlegs i love a show I can listen to without being annoyed by the live elements so if it sounds distant or muddy/boomy or is more crowd than band or has a bad mix or is poorly recorded etc. I listen once and then put it away. Even a bad setlist condemns a show to the boxes for me.

With the prevelance of the iPod my definition of a great bootleg is a show
that I can stick on my iPod and enjoy when they tracks come up in my always random playlist.

I gotta start with
1/10/90 - best setlist ever and very decent sound for so early an audience recording.
5/19/96 - yokohama, got it rom a japanese trader back in 96 and still love it.
8/16/97 - wembley - jon having fun outside the Bon Jovi element
5/24/98 - allentown - saw richie live in a small setting with open taping
6/23/00 - acoustic storytellers
11/20/00 - best OWN show
5/8/01 - played 1/2 of new jersey album
7/21/01 - great show/recording
2/16/03 - eve of destruction show
7/7/08 -

I'm sure others will disagree and something like this is very personal to each collector.
Dave