Hell is a very serious topic.  Also the way the Bible describes Hell is your worst nightmare.  if anyone has ever seen "Ghost" with Patrick Swayze and Demi Moore, the way Hell was depicted with groanings (biblical) and dark shadows that sucked you into the netherworld (unbiblical) totally freaked me out and reminded me why Salvation is so awesome and life saving, and why I should keep trying to witness to people.

EGW quote:

The Great Controversy, page 674, paragraph 1
Chapter Title: The Controversy Ended
"I saw a new heaven and a new earth: for the first heaven and the first earth were passed away." Revelation 21:1. The fire that consumes the wicked purifies the earth. Every trace of the curse is swept away. No eternally burning hell will keep before the ransomed the fearful consequences of sin.

Life Sketches of Ellen G. White, page 49, paragraph 2
Chapter Title: Separation from the Church
She answered: "The Bible gives us no proof that there is an eternally burning hell. If there is such a place, it should be mentioned in the Sacred Book."

this is the basis for Adventist belief 
 

Hoekema's view on Annihilation which is consistent in refuting the concept of Annihilation with hell etc.

I think the seriousness of hell speaks more to us about the gravity of sin rather than God's mercy.  God's mercy is demonstrated in His plan of Salvation.  His Wrath, and He does have wrath, is demonstrated in hell.  God is in Hell too, except those in hell will not be experiencing God's other attributes.

an exegesis:
 
 now i can conceive the whole adventist thread:

1. since the soul sleeps, this means (somehow) that death is total death the soul and body are one, the spirit returns to God (like in star wars: the life force ;))
2. because of this, this proves that the soul is not eternal, and that God will annihilate the wicked.
3. this also is good because if you reject salvation after you are saved THEN you don't have to face eternal torment (God wouldn't be that cruel), you just wink out of existence.

one falls, they all start to fall.

again I'd like to emphasize that our concept of the soul should stem from a holistic approach to the Bible.  SDA's mainly rely on the Old Testament for their support of soul sleep, but as you'll see, the OT people did not have a very clear understanding what the after life was like.  (who could know?)

in my reading of soul-sleep, I read that in Psalms, the Israelites did not have a complete picture of what death was aside from the obvious that it was the opposite of life. there they mourned in the Psalms that they could no longer praise/thank God, and a Hebraist said that it means they could no longer praise God in the public congregation of the living. so that accounts for Psalms. it's talking mostly about the mortal life, the physical death consequences. they also thought that the death of a righteous man was much better than the death of a wicked man.

Ecclesiastes is talking about how everything is useless without God. One person noted that Ecclesiastes is poetry and not intended for theological support of death.

Ec 9:5
For the living know that they shall die: but the dead know not any thing, neither have they any more a reward; for the memory of them is forgotten.

(so I'm not distinctly articulate on the subject yet, but i'm working it out, ok?)

in psalm 146:4 it says the thoughts will perish when they die, but it's also translated as plans will perish.

I think it's talking about the mortal life, the physical body not being able to complete plans or have thoughts any longer, but not the soul.

so, the bottom line there that there is reward after death as we do know (Matt 5:12, 1 Cor 3:14, Rev 22:12)

we do know that souls remember things because in Revelations 6:9-10, the souls of the martyrs are crying out to God for vengeance and this is before the second coming. or something, hm. anyway, they sure seem like they do remember.

also, we know that

Jude 1:14
And Enoch also, the seventh from Adam, prophesied of these, saying, Behold, the Lord cometh with ten thousands of his saints,

these saints are the ones that are already with Him in heaven.

anyway, there is a soul and not soul sleep, otherwise Paul would not have yearned so deeply to be with God

2 Corinthians 5:8
We are confident, I say, and willing rather to be absent from the body, and to be present with the Lord.

of course Matt 10:28 is a pivotal verse:

Matt 10:28
"Do not fear those who kill the body but are unable * to kill the soul; but rather fear Him who is able to destroy both soul and body in hell.

And a parallel passage:

Luke 12:4-5

"I say to you, My friends, do not be afraid of those who kill the body and after that have no * more that they can do. But I will warn you whom to fear: fear the One who, after He has killed, has authority to cast into hell; yes , I tell you, fear Him!

dear friends, the term: destroy both soul and body in hell is the same idea as casting into hell. Here we see that destroy does not mean annihilation, but is a metaphor: to devote or give over to eternal misery in hell.

the word destroy is also used by demons howling encountering Jesus:

Luke 4:34
"Let us alone ! What business do we have with each other, Jesus of Nazareth ? Have You come to destroy us? I know who You are--the Holy One of God !"

cross referencing:

Mt 8:29
And they cried out, saying, "What business do we have with each other, Son of God? Have You come here to torment us before the time ?"

so destroy here means to torment. i find it particularly interesting that the demons already know their fate is to be tormented.

TORMENT:
Basanizo 1:561,96
Phonetic Spelling Parts of Speech
bas-an-id'-zo /cgi-bin/lexicon.pl?id=0928g/cgi-bin/lexicon.pl?id=0928g Verb

Definition
1. to test (metals) by the touchstone, which is a black siliceous stone used to test the purity of gold or silver by the colour of the streak produced on it by rubbing it with either metal
2. to question by applying torture
3. to torture
4. to vex with grievous pains (of body or mind), to torment
5. to be harassed, distressed
1. of those who at sea are struggling with a head wind

DESTROY:
Apollumi 1:394,67
Phonetic Spelling Parts of Speech
ap-ol'-loo-mee
Verb
Definition
1. to destroy
1. to put out of the way entirely, abolish, put an end to ruin
2. render useless
3. to kill
4. to declare that one must be put to death
5. metaph. to devote or give over to eternal misery in hell
6. to perish, to be lost, ruined, destroyed
2. to destroy
1. to lose

in this we can see that:

a. there is no soul sleep.  because
    i. God says not to fear one who can destroy the body.  if body/soul/spirit were one (and the body died therefore all of it died then you would have a lot to fear, because someone could kill your soul.
    ii. hell is torment, not annihilation.  the verb destroy means the same as casting into hell.  also destroy is used as a synonym for torment
    iii. if Paul desired to be absent from the body 2 Cor 5:8, did he desire to be absent and unconscious?  or to be completely dead?  no, he desired his conscious soul to be with God
    iv. also there is no soul sleep because of the martyrs crying out for blood beneath the altar in Revelations, and that Enoch (a very godly man, I might add) said that ten thousands were coming back with him at the 2nd coming.

also, there is the "Today, you will be with me in Paradise." as Jesus said to the thief on the cross beside Him.  now, my ex contends that it's just an expression like: "Right now, I tell you that you will be with me in Paradise (eventually)."  Do you SEE the contortions he needs to go through to come up with that definition?  another case study of scriptural twisting (or gymnastics as I like to call it).

also there is the passage where those that are saved go on into eternal life, and those not into eternal hell.  the greek word is ainois, which my ex contended meant 'to the end of the age' which is true in some contexts, but if you believe that eternal life is for forever, then you have to believe that eternal hell is for forever also.

more verses on hell:

job 24:21-26, psalm 49:10-15, daniel 12
romans 8:1-16, 2 Thessalonian 1:3-12, Jude 5-13, Revelations 20:11-14, Jude 17-23