Suicide is the ultimate rejection of God's offer of grace. Christ has defeated death and offered life to us, and to kill oneself is to completely reject Christ's gift and embrace Hades.
Of course, we may still hope that one repents immediately before they die. It's always possible, for several methods of suicide. But to die without reaching for Christ is to be eternally condemned.
>So example im a victim in the twin towers two choices, do i burn, or drop dead from the 114th floor? Well in my assumption God, is good, so im not gona burn in this life when im dead either way might as well jump.
Ah… That's a bit difficult. When there is no realistic possibility of surviving in a situation, is choosing to jump much different from choosing to burn? I would say that there is no real choice here, and one doesn't "choose" to die either way, so it's not suicide in the sense usually meant.
Concerning suicide as it is usually meant… I think that suffering from a mental illness like clinical depression softens the gravity of the act, as one's mental capability to accept or reject God is affected. But it doesn't excuse it either. Suicide remains a grave sin, and those who die from suicide cannot get a funeral.