Haven't done a packed concert in a while but one came through my town. Local favourites Municipal Waste, along with thrashers Toxic Holocaust and punk bands In Defense (pictured here) Ramming Speed and Unsacred.
I knew the show would be packed so my best chance to get some good shots was for the opening acts. There was serious moshing and stage diving going on throughout the entire show so I had to watch where I was, lest I get sucked in and have my camera gear damaged.
I settled on ISO1000, typically with a shutter speed of 1/200 and of course, shot wide open, f/1.8 to 2.8, depending on the lens used. I fluctuated between the 50mm, 28mm and the 80-200mm. The venue was well known (to me) to have very iffy lighting, so I was pleased when I discovered they'd done some upgrades.
Furthermore, the venue was using a lighting computer with a set progression of lights so it was very easy to time.