What is the Biblical support for Hell as a singular concept? One of the common tenets of Christian Universalism (as well as Annihilationism) is the non-existence of Hell as an eternal punishment for non-Christians, that everyone has been granted salvation through grace (regardless of actual belief).  This is often supported by referencing issues of translation in the creation of the word "Hell" altogether, in the form of the claims that all places that "Hell" occurs in translations of the Greek refer to:


Sheol/Hades: the unknown, afterlife, underworld, or a grave
Gehenna: either a physical place in Israel, or a representation of burning (referred to by Universalists as a place of spiritual purification - of the Greek puros, a "refining fire")
Tartarus: warrants it's own discussion - a place where the fallen angels are kept, also present in Greek myth
Grave or pit


As a reference, there's a chart of some words selected in various translations here.  Additionally, there are often challenges of the usage of the word "eternal" in translations, as well as the concept of fire (or the Lake of Fire) being synonymous with "Hell."

Is there a basis in scripture for the concept of an eternal "Hell" for non-Christians, and how do particular denominations and groups approach the idea of an eternal "Hell"?
This is what we know of "Hell".

It's a place of darkness

Jude 1:13 (NIV)


  They are wild waves of the sea, foaming up their shame; wandering stars, for whom blackest darkness has been reserved forever.


It's a place of torment

Luke 16:28 (NIV)


  for I have five brothers. Let him warn them, so that they will not also come to this place of torment.’


It's a place of fire

Jesus says in Matthew 13:42 (NIV)


  They will throw them into the blazing furnace, where there will be weeping and gnashing of teeth.


It is eternal

Mark 9:48 (NIV)


  where “‘the worms that eat them do not die, and the fire is not quenched.’


It is separation for God

Matthew 25:41 (NIV)


  “Then he will say to those on his left, ‘Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels.


God does not want you to go to Hell

John 3:17 (NIV)


  For God did not send his Son into the world to condemn the world, but to save the world through him.


Those are the highlights.  There are many other places that support each one of those facts.  I just picked a nice representative of each verse.