I am a location recording engineer as well as a studio engineer and routinely record gigs, shows, jazz sets, classical stuff and simple location stuff so I bounce between a couple rigs ranging from 16 channels to 48.
I use a 003 16 channel pro tools rig for small gigs and jobs.
I use a Pro Tools HD2 with 24 channels (upgradeable to 48 if i need) for bigger jobs.
Generally I also have an Alesis HD24 as backup to the HD2 rig as these jobs are more important and absolutely cannot fail. Infact, I usually always have some sort of redundant backup somewhere, even if it is a simple stereo Zoom H2 or Laptop.
G