I think the story of Lazarus that Jesus tells is a good one, in Luke 16...I apologize if that has already been cited. While it doesn't speak of eternal punishment, Jesus does use it to tell that there
is life after death, and a place of
punishment and a place of
paradise.
To better understand the story of Lazarus, Hell, "Hades" and "Sheol," I recommend this page:
http://www.layhands.com/DidJesusGoToHell.htm Speaks of the existence of Hell now and the future existence that Revelations speaks about. Very good link in my opinion.
Also this one:
http://www.matthewmcgee.org/helwords.html
It's important to understand the background of hell in discussions like this.
I also like Daniel 12:2-3. The "everlasting" here literally means (according to BlueLetterBible): "1) long duration, antiquity, futurity, for ever, ever, everlasting, evermore, perpetual, old, ancient, world
a) ancient time, long time (of past)
b) (of future)
1) for ever, always
2) continuous existence, perpetual
3) everlasting, indefinite or unending future, eternity.
In regards to the immortality of the soul, Jesus telling the theif that "today" you will be with my in paradise is a good one, which literally means according to BlueLetter: "1) this (very) day), or 2) what has happened today."
Here "breath" and "spirit" are not the same things: "Jesus called out with a loud voice, "Father, into your hands I commit my spirit." When he had said this, he breathed his last." (Luke 23:46).
Also Ecclesiastes 12:7 and 2 Corinthians 5:6-8, another one of my favorites.
-McQ 8-)