I pan my drum mixes (we mike and record everything separately) so that the relative positions of each element in the sound field is the same as if I was standing right in front of the drums. It adds some depth to the sound. I do keep the bass drum and snare very close to center since that's where they are when I stand in the middle.
Check out
http://www.unpronounceable.com/ for some examples of this.
I generally keep the bass dead center except when there is extensive looping. In that case, I pan the raw and looped bass slightly to the left and right. Sometimes I do pan the guitar slightly to the left and bass slightly to the right. Again, to mimic the sound of standing in front of the band.
I'm still experimenting though.
- Dave