This list is not just based on vocal prowess, criteria also include song quality, impact on industry, ability to play an instrument and/or craft a song, and of course my personal bias...
10. Rick Florian (WhiteHeart)
9. Matt Hammitt (Sanctus Real)
8. David Crowder (DavidCrowderBand)
7. Jon Foreman (Switchfoot)
6. Bear Rinehart (needtobreathe)
5. Michael Barnes (Red)
4. Jon Micah Sumrall (Kutless)
3. Bart Millard (MercyMe)
2. Mac Powell (Third Day)
1. Marc Martel (of downhere)
Some notable misses (like dc Talk)? Check here.
Honorable Mentions:
Mark Hall (Casting Crowns)
Jamie Rowe (Guardian)
Dan Haseltine (Jars of Clay)
Derri Daugherty (The Choir)
Edin Adahl
Kevin Young (Disciple)
Thoughts?