Check out mp3.com's musicvine. It's a visual depiction of the relationship between various bands, and from my test case it works REALLY well. I put in Dogwood, and BAM! the five closest bands in the graph are Craig's Brother, MXPX, Hangnail, Ace Troubleshooter and 38th Parallel. From there, it extends out in clearly-defined ways: CB branches out to secular punk (New Found Glory, Blink 182, Yellowcard) as well as emo (Further Seems Forever, Taking Back Sunday). 38th Parallel branches to Christian rap-core (POD, Project 86, Blindside) and from there to Christian hardcore (Zao). Hangnail and Ace reach out to Christian punk (Philmore, Relient K), and from there to Christian alternative in general (Kutless, Switchfoot, Jars of Clay). It's mindblowing and accurate.
If you center on Craig's Brother, you get visual proof that the band does straddle the Christian and secular markets. There are two poles; on one side are secular bands (MXPX, New Found Glory, Yellowcard, Something Corporate), and way on the other side are Christian bands (Dogwood, Hangnail, Project 86).
It's addicting. Blindside: it's part of a triumvirate with Project and POD. Besides that, there are three groups: the secular rap-rock/alternative section, with Linkin Park and Chevelle; a nearby constellation consisting of the larger Christian alternative bands; and a black-and-blue group in the corner representing Christian hardcore -- Living Sacrifice, Norma Jean, Demon Hunter.
CHECK IT OUT NOW!