@Enaj,
I'm inclined to agree with marknoble - an individual is the only person who ought to have the most control over their destiny, and if this includes choosing to kill themselves then this is acceptable. However, the choice to commit suicide is more acceptable depending on how 'reliably informed' it is and how objective and rational the agent is, and this gets onto dodgy ground as it is hard to be reliably informed when we don't know for certain if anything happens after we die, and there is the argument that certain mental illnesses which may lead to a person having suicidal thoughts skew this rational capacity.
But regardless of how an individual may be swayed in making such a choice, I would argue that they still possess that capacity to choose for themselves, so even if they are 'unreliably informed' they should still be able to make that decision.