This issue is too complex for a blog post, but here are several reasons that could tip one towards Amillennialism:
- Death ends when Christ returns.
- Revelation 20 is a heavenly vision.
- In Revelation 20, Satan is bound with respect to deceiving the nations.
- Revelation 19 shows that the nations are wiped out.
- Surely Paul would have mentioned a future millennium if there was one.
- Christ is reigning over his enemies now.
- There is one resurrection for the just and unjust.
- Revelation 21-22 quotes Isa 60 and 65 as referring to the eternal state.
- The land promises are fulfilled in the new earth, not an earthly millennium.
- It doesn't make sense to say that unbelievers will continue to rebel in the presence of the risen, glorified Christ.
- The creation is freed from the curse when Christ returns.
- Resurrected bodies mingling with non-resurrected bodies seems strange.
For more on amillennialism, see Riddlebarger's A Case for Amillennialism, Hoekema's The Bible and the Future, or Venema's The Promise of the Future. Here is a book list.