Jesus. Most people whom are Christians have no problem with that, but the sects themselves have huge doctrinal issues with our religion and can't accept our understanding of Jesus. To them it's heresy that we be considered Christian.
But just as RG3 says, we are Christians and Christians need to learn to stick together as I believe persecution against religion will escalate. We should stand up for Baptist, Methodist, Pentecostal (although some of them are pretty extreme) and they should stand up for us. I'm talking politically. none of needs to swear fealty to each others' doctrine, just that we are all trying to follow Jesus.