This is one of those areas where theology often goes beyond what God says in the Bible, and that always causes a problem.  There is quite a debate over this and a lot of confusion, straw man argumentation, etc.  Actually, you could see how a person could rationalize a case for either the restitution of all things or the idea that many will be lost and never restored (though there are many positions, not just two).  And about half of all Christians take each view, though there are many variations of how each view is interpreted, some Scriptural and most anti-Bible.  Some people even claim that there is no hell or that hell isn't that bad.

Our local assembly is operating under the authority of that move of the Spirit that began in 1948.  In that move of the Spirit, several things have been restored to the church.  One of these things is the office of the apostle.  Apostles were set.  As a result, the apostles receive the revelation of the interpretation of Scripture.  God spoke to them very clearly about this particular matter.  Please check the links in the scriptures below.

Matthew 25:46 And these shall go away into eonian correction: but the righteous into life eonian.
2 Thess. 1:7 And to you who are troubled rest with us, when the Lord Jesus shall be unveiled  from heaven with his mighty angels, *
8 In flaming fire supplying justice on those who know not God, and that obey not the gospel of our Lord Jesus Christ:
9 Who shall be corrected with eonian death from the presence of the Lord, and from the glory of his power;
Jude 1:7 Even as Sodom and Gomorrah, and the cities about them in like manner, giving themselves over to fornication, and going after strange flesh, are set forth for an example, suffering the justice of eonian fire.

You also may want to read this: http://seekfind.net/Bible_Dictionary__Define_Hell__Definition_of_Hell.html

this: http://www.SeekFind.net/What_About_The_Three_Incompatible_Principles_In_The_Bible.html 

and this: http://seekfind.net/Bible_Dictionary__Define_Universalism__Definition_of_Universalism.html