Suicide is a selfish act if it is not discussed and agreed upon by those whose lives you affect on a daily basis, as they have to live with the mess you may or may not leave behind. So if you are terminally ill and want to end it, discuss it agree to it get your affairs in order and do the act.
On the other hand if you are just a depressed fool that wants to end it all, know that you are nothing more than a selfish coward. At least have the good sense to put your affairs totally in order, do not choose a messy and horrific way to die where a family member will find you as you will give them nightmares for the rest of their life. Though personally I believe that to commit suicide because you see no light at the end of the tunnel is a cowards way out - get a grip on life and deal with it. Harsh - but my opinion.
I believe it is a weakness but it also takes strength to commit the act. One of lifes most basic instincts is to survive, so when you go against that instinct to cut your life short, it has to take courage and discipline of some degree to actually carry out the act of killing yourself.
In my opinion, you do not hang about to make anyone happy, that makes them selfish and you an idiot. If you are planning on going, get your house in order and all the people in your life to accept the idea first, then go ahead. Hanging about to please a loved one is in a way is asking them to bear a dreadful guilt for the suffering you may be enduring. (this is said for the terminally ill)
I believe suicide is only permissable when you are terminally ill and do not want to go through the whole process of dying by illness, in this instance it is an act of courage and kindness to those you love so they can remember you whole and healthy before the bad sets in.
Suicide by the depressed is a cowards way out.
If you are in a situation of absolutely no hope eg. stuck in an air pocket below the water line in a sinking ship and there is no way you are going to get back to the top then it is okay to sink into the water and drown or put a bullet in your head.
Get trapped in some secret place inside a pyramid and know you are going to die a slow death by starvation etc - then it is okay to chose a bullet instead - get my drift? Okay now I am talking tripe! :

: gotta go!