How Much Insulation is Too Much?

No I am not talking about R30 in the attic. I am talking about barriers between the church and the world. The church we see in the New Testament appears to be keenly aware of the issues in their surrounding culture and actively engaged in being in the world but not of it. That being said just how insulated is the church today? I know some churches are less insulated than others. Some have support groups, active ministries that engage their communities, etc. Just how insulated is too insulated? How far out of our comfort zones should we be willing to get in order to help the world be a better place? Is there any level of insulation that is appropriate? If so where do you draw that line?