Defining the Church

How would you define "the church"?  It's essential we know what we're talking about.

Here's the Driscoll's definition from Vintage Church:
The local church is a community of regenerated believers hwo confess Jesus Christ as Lord.  In obedience to Scripture they organize under qualified leadership, gather regularly for preaching and worship, observe the biblical sacraments of baptism and communion, are unified by the Spirit, are disciplined for holiness, and scatter to fulfill the Great Commandment and the Great Commission as missionaries to the world for God's glory and their joy.
I'd have to agree.