I've photographed the Plain White T's several times over the last couple years, from their 2008 run on the Honda Civic Tour to their headlining tour in 2009 for Big Bad World, and every time it's been a blast. On their 2011 tour for Wonders of the Younger, the T's high energy show was no exception.
I have to say, I was pleasantly surprised by the lights for this show. Even though this was arguably a smaller setup than the Plain White T's last concert at the Pageant, the lighting treatment was much more photogenic.
One very interesting aspect here was the use of uplighting on the band. While uplighting is normally used as a contrast to the normal overhead lights and used separately, this tour used them in tandem, which created some interesting two-color treatments on the band members.
Overall, there was enough to shoot pretty comfortably between ISO 2500 and 3200 with f/2.8 zooms.
If you do get the chance to shoot Plain White T's, definitely take it. Even if you don't listen to these guys, they put on a heck of a show, with tons of movement from Tom Higgenson especially.