[kevinvw]

This verse is the biggest advocate for the gap theory and I think in light of certain other passages it doesn't support any gap at all.

Mat 24:36 But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.
Mat 24:37 But as the days of Noe were, so shall also the coming of the Son of man be.
Mat 24:38 For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark,
Mat 24:39 And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be.

In this passage Jesus is talking about the second coming and he compares it to the days of Noah when the people didn't hearken to the warning of the coming judgment.

2Pe 3:1 This second epistle, beloved, I now write unto you; in both which I stir up your pure minds by way of remembrance:
2Pe 3:2 That ye may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us the apostles of the Lord and Saviour:
2Pe 3:3 Knowing this first, that there shall come in the last days scoffers, walking after their own lusts,
2Pe 3:4 And saying, Where is the promise of his coming? for since the fathers fell asleep, all things continue as they were from the beginning of the creation.
2Pe 3:5 For this they willingly are ignorant of, that by the word of God the heavens were of old, and the earth standing out of the water and in the water:
2Pe 3:6 Whereby the world that then was, being overflowed with water, perished:
2Pe 3:7 But the heavens and the earth, which are now, by the same word are kept in store, reserved unto fire against the day of judgment and perdition of ungodly men.
2Pe 3:8 But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.
2Pe 3:9 The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.
2Pe 3:10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.

I think the biggest reason why people see this verse as supporting some flood that happened between Gen 1:1 and 1:2 is because they read it without the context. Notice the similarity between the warning of Jesus Christ and this passage.

The scoffers are saying that the Lord isn't coming back and that nothing different has happened since the beginning just like the people didn't believe Noah that there was going it was going to start raining. It says they are willingly ignorant of the flood that wiped out the people in the days of Noah. They refuse to believe that God killed those men with a flood and they refuse to believe that God came to earth as a man, died, rose from the grave, ascended into heaven, and is going to come back to kill them. Peter warns us to not be willingly ignorant like these men because the Lord is not slack concerning His promise even though it seems like He's taking a long time. He will come back and kill scoffers just like He killed the scoffers in the days of Noah.

Both Jesus and Peter are talking about the second coming, and they both liken it to something. Jesus likened it to the days of Noah. Some people think Peter is talking about some mysterious time period between Gen 1:1 and 1:2. I think it's evident that he's repeating the same warning that Jesus gave, and not telling us about some period of time so mysterious that it hides between two verses.

You say, why does Peter talk about an old world and the world that is now. Well look at 2 Peter 2:5.

2Pe 2:5 And spared not the old world, but saved Noah the eighth person, a preacher of righteousness, bringing in the flood upon the world of the ungodly;

Unless Noah lived between Gen 1:1 and 1:2, the old world was the world from the beginning of time to the flood of Noah, which would make the world that is now the world from after the flood to the second coming of Jesus Christ. After which, the Lord makes the new heavens and the earth.