Leaving Church - Part 4b - Why Church?

Leaving Church - Introduction
Leaving Church - Part 1 - Those Left Behind
Leaving Church - Part 2 - How Not to Leave
Leaving Church - Part 3 - Why Leave?
Leaving Church - Part 4a - Why Church?

I have been looking into what people typically say the purpose of church is and why we have to meet together. I have been struggling with this post all day, so please bear with me if I'm unintelligible.

Some people say we need church:

To fellowship with believers
For corporate worship and prayer
To receive sound biblical teaching
To receive absolution
To receive the sacraments
To evangelize the lost
To maintain a public testimony
To edify or build up one another

..and so on...

In asking this question, you could ask 100 different people and get 100 different answers. Granted, there are numerous passages of the New Testament that highlight the purpose of 'church', all of which are important. The things I listed are certainly all things that take place in church, things that happen there. But are they really the purpose of church and do all those things have to happen in order for a gathering to be 'church'?

Here's a concise view from the New Testament, which I'm sure you're all familiar with:

Acts 2:42-47 NIV "They devoted themselves to the apostles' teaching and to the fellowship, to the breaking of bread and to prayer. Everyone was filled with awe, and many wonders and miraculous signs were done by the apostles. All the believers were together and had everything in common. Selling their possessions and goods, they gave to anyone as he had need. Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts, praising God and enjoying the favor of all the people. And the Lord added to their number daily those who were being saved."

Or, in other words:

Acts 2:42-47 MSG "They committed themselves to the teaching of the apostles, the life together, the common meal, and the prayers. Everyone around was in awe—all those wonders and signs done through the apostles! And all the believers lived in a wonderful harmony, holding everything in common. They sold whatever they owned and pooled their resources so that each person's need was met. They followed a daily discipline of worship in the Temple followed by meals at home, every meal a celebration, exuberant and joyful, as they praised God. People in general liked what they saw. Every day their number grew as God added those who were saved."

So to keep it simple:

Teaching
Life Together
Common Meals
Prayer
Signs & Wonders (The interpretation of which is up for debate.)
Harmony
Everyone's needs are met
Worship
Celebration

Notice how little is said about when, where, and how? The who (followers of Christ) and the why (to praise God) are obvious, but only the what seems important enough for a mention.

A few questions form in my mind:

1. Could any place where all these things are done be considered to be church?
2. Conversely, could a place where not all of these things are done be considered NOT to be church?
3. Is there any specific method to these things?
4. If they are not done by a commonly accepted method, does that invalidate it as a church?

What do you think?