I started this thread four months ago and haven't been back in this forum much since. I can't believe its still going. It has to be the oldest thread going...
Skillet had my vote, although mainstream Christian gets lamer the more you listen to it (sorry). Some other great bands 'o Christians are Chasing Furies, Caedmons Call, Massivid, Saviour Machine, and a band that is no longer around, Wedding Party.