I recently saw The Innovators perform, and I thought they deserved a mention here. This is going to sound a bit odd, since they are an explicitly Christian music group, meaning that their songs are basically all songs of praise. (For those of you who aren't regular readers, I'm basically an atheist... so, pretty much the exact opposite of The Innovators' target audience.)
Musically, they're very good: there's nothing sloppy or unprofessional about their performance. They opened with a couple of praise songs done in a very catchy a cappella/barbershop style. They're originally from Zimbabwe, so the next couple of songs were done in their native language (Shona, I think) and were, for me, the most enjoyable part of the show. Though I have to say, the doo-wop version of Silent Night that they closed with was fun, too.
Basically, if you're looking for a music group to include in a praise service or something like that, these guys are very good and you should check them out. They're mostly performing in and around the Dallas/Fort Worth metroplex right now, but (based on their calendar) it looks like they're willing to travel.
Now, if explicitly inspirational/praise-oriented Christian music isn't your thing, you probably won't enjoy The Innovators anywhere near as much. They're not a group that I'd recommend for non-Christians or ex-Christians, as the all-praise-all-the-time vibe tends to wear on my nerves. But they knew what they were doing and they did it well, so if their material suits your beliefs you're good to go.