So much of end times hangs on how and, more importantly, when the 1000 years of Jesus's reign on earth will be. This makes Chapter 20 the most debated of the book of Revelation. There are a number of views, and of the ones discussed here we recognise that even these are generalisations. We also recognise that if you hold one of the views here and it differs from someone else's you won't lose your salvation because of your interpretation. Please also know that I am not an expert in eschatology (the study of last things) and so I have put in links to additional readings.
1. Post-Millennium and Preterist
Here the main idea is that Jesus Christ will come again "after" (i.e. post) the Millennium, (a 1000 year reign which may be symbolic or literal). In its purest view the church we currently sit in the church age, that is before the Millennium.
Partial Preterist takes this idea a step further and has the Fall of Jerusalem and the destruction of the temple in 70AD and Jesus's second coming in judgement. However, the Last Judgement will be after the Millennium (which we are currently in). This means that everything up to Revelation 20:6 has already happened, i.e. partial.
Hyper or Full Preterist takes it even further again and expresses that the Last Judgement has happened as well, therefore all of Revelation has been fulfilled. This, as a result, means that we are living in the Eternal Kingdom, the new heaven, and the new earth. This is heresy as it disregards the resurrection and a lot of God's promises around His inheritance that we will share.
2. Premillennialism puts the second coming of Christ before (pre) the Millennium. The majority believe that a period of tribulation will be experienced on earth, however, a pre-, mid-or post-tribulation rapture may take place depending on your reading of the scriptures. The premillennialism view seems to be the most commonly accepted currently and helps us read Revelation 1:19
“Write, therefore, what you have seen, what is now and what will take place later.
Chapter 1 is what you have seen (Jesus), Chapters 2-3 being what is now (the 7 churches and the church age), while chapter 4 onwards is what will take place later.
With this view, the term dispensationalism is often included. This doesn't change the timeline of events but does add some further considerations. There are two types; Traditional and Progressive. Some more reading on this can be found here at Got Questions.
3. Amillennialism is the idea that the book of Revelation is not prophetic, but rather it is full of timeless truths. We are living in the Millennium now, that Satan is bound (be it some sort of leash). The Gospel is preached. The judgements presented are just examples of what we are experiencing today, e.g. the natural disasters detailed in the trumpets are an example of the natural disasters seen now. The 144,000 is just 1,000, representing a large number, x 12 (a number representing complete), therefore it is just a metaphor for the church.
This makes interpretation quite flexible, therefore it could be bent to support any argument. It washes all the vivid language and graphic detail away and oversimplifies the layers of meaning that the original audience would have understood. The good aspect of this is that we read Revelation and it is written to encourage us, God's people, to persevere in our faith. Because it looks at the biblical truth today's audience can take away, it makes it very applicable to our daily lives.
4. Historicist is the final view and is quite popular with Seventh-day Adventists (apparently). It overlays world history on top of the events found in Revelation. It was very popular in the 1500s and predominately uses the 7 churches found in chapters 2 and 3 as phases of the church age.
This means it has been recut every generation and therefore it is constantly changing and being reworked to fit human history.
A lot of this chapter can be seen in Ezekiel 36-48. Gog king of Magog is adapted to be two characters in Revelation 20, Gog and Magog. These represent all nations from the four corners of the earth. Jewish writers at the time used Gog to gather all nations against God's people.
We see Hades (the realm of the dead) and Death being judged, those not raised (1st resurrected) will be damned.
For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first. (1 Thessalonians 4:16)
A good article on the 3 main views can be found here at Evangelical Focus Europe.
A blog focused on the post-millennialism view can be found here at postmillennialworldview.com.
A criticism of the historicist view can be found here at Spectrum Magazine
(please note this is a Seventh-day Adventist Church community magazine).