RenHoek said:
The body is made up of many types of members.
Agreed. There are various giftings, and people of different ages, ethnicities, languages. Having different types of congregations for different people is great. 
RenHoek said:
There is no one best way to do church. If a large group of people pool resources in a grand fashion to shape righteous change, who are you to tell us it is wrong, or do you have scriptural reference to the correct number?
There is no specific number given in scripture. However, we know from scripture how a congregation needs to operate. In order for a congregation to operate scripturally, I see no better way than to have a small congregation.
Here are some things we are told the local congregation must do:
1)Enforce discipline
2)Observe the Master's (Lord's) Supper.
3)Exercise the spiritual gifts that ALL believers have been given.
Enforce Discipline
In order for a congregation to enforce biblical church discipline (Matt 18, 1Cor 5), the participants must know each other, and know each other on an intimate level. How else can one believer know if the other is sinning? This is accomplished much easier when the congregation is small. In addition, how can a unrepentant believer be formally expelled from a congregation if the congregation is so large that people can come and go as they please with anonymity?
Observe the Master's Supper
We learn in Acts 20:7 that the disciples broke bread on Sundays. According to early church historians, the Master's Supper was no snack. Not only is the meal based on the Passover Seder (a Jewish feast), but it is also referred to as the "Love Feast" by early Christians. If this meal was truly meant to be a full dinner, how would it be logistically practical to serve a meal for 50+ members every Sunday?
Exercise Spiritual Gifts
All believers are given gifts. All believers should be using those gifts. How can we ever use these gifts in a significant way unless we are in a participatory, inter-active meeting? How can every believer ever interact on a meaningful level when we are one person sitting among thousands in an auditorium watching the church service happen? It seems the only opportunity to even share a quick word of encouragement or teaching in a Megachurch is in the context of a smaller group of friends or believers gathering before or after the service.
RenHoek said:
It is not the churches job to make you a better Christ follower. It is up to you to seek Him.
It is both my responsibility to seek Him, and your responsibility to encourage me. That's what assembling together is all about. (Heb 10:24,25) It is also every believer's responsibility to keep his brother accountable and use the method of discipline that Jesus gave us (Matt 18, 1 Cor 5).
RenHoek said:
I would rather see the lost/weak in church hearing a good message than have them stay home and not have the exposure. Should we hang out with people regularly who are problematic without repentance? Probably not, but Christ was criticized by the Pharisees of His time for spending time with these people. It is our call to help them find their way.
I would rather see a lost person hear a good message than sit at home also. However, we are called to "go" (Matt 28:19) and preach the good news, not wait for the lost to show up. Church meetings are for believers, not unbelievers. Although we can bring an unsaved friend, the meetings must be designed to edify the church, not to evangelize. The Church is meant to be a pure, righteous community. Sin is very contagious - we must purge the Church of those who call themselves Christians, yet fail the discipline process.
-Panacea

John 13:35