Audio Adrenaline is pretty good. For harder/metal stuff, Thousand Foot Krutch has pretty good work.
Most seem to like Third Day, although they aren’t REALLY rock. Check out their album Wire.
Lifehouse is presumably Christian. I know lead singer Jason Wade is the son of a preacher. I’ve found that with many Christian songs, the subject matter is either God or a girl. Most of Lifehouse’s songs are ambiguous like this.
Guitarist Jonny Lang’s father was also a pastor, IIRC, and some of his music has religious influence.
Switchfoot is branching out more mainstream, I think, but they started (and probably still are) a Christian band.
I haven’t listened to and POD since their 2001 album, so I can’t say on them.
Relient K is more punk/pop rock, but if that’s what you’re going for, they have an alright band. A similar Christian band of this genre is FM Static (I’ve only heard their first album though (they just released their second not too long ago)).
You can check out most of these on iTunes’s 30 second samples. Songs by artist I would recommend are:
Audio Adrenaline: Underdog. They also did a good cover of Free Ride (Edgar Winter Group)
Thousand Foot Krutch (Harder/Metal sound): Rawkfist, Step to Me
Third Day: ‘Til the Day I Day, Blind
Lifehouse: Hanging By A Moment
Jonny Lang: Lie to Me
Switchfoot: Dare You to Move, Meant to Live
POD: I really got nothin’, but I remember Satellite being an alright track.
Relient K: Be My Escape, Pressing On
FM Static: Something to Believe In, October.
Hope you don’t think every single one of these felches goat testicles, but people have varying opinions on music, so I hope you find what you’re looking for.