I've always sided for the ability to choose in this because I really do think there are things worse than death, especially when you're assured there's no recovery before the end.
I don't give a fuck what anyone else does.
If I have to, I will die while living off of a tube because my religion doesn't allow me to commit suicide. I also won't tattoo myself for the same reason. (I do choose not to follow some laws, yet I follow others)
Just because I personally believe anyone who commits suicide is going to hell (Note: I don't actually believe that previous statement), doesn't mean I'm going to stop him or her. Not my place.
=]
Also the question of "What happens if someone changes their mind at the last minute" needs to be answered or at least have some sort of legal context to it. I haven't spent a huge amount of time pondering the issue, but the opening of legal loopholes is the only thing that I could possibly see blocking this.
Well, I guess the other thing might be some sort of required counselling to prevent impulsive emo teens (or similar) from using such a thing (i.e. make sure that people are in a rational frame of mind when making the decision, not just running off to die because of a break-up).
As far as I know where euthanasia is currently legalized the person has to pass a psych test to see if they are of sound mind and that they're not being coerced into making the decision. If the psychiatrist feels something is off then the euthanasia isn't performed (at least in theory). The person also has to suffer from a terminal illness that the doctors at the euthanasia place can verify.
Emo kiddies aren't going to pass the psych evaluation or the terminal illness evaluation. However there should be a chicken clause that the person getting euthanised still has the ability to back out right until the end.
However with legalised euthanasia the state would be required to cover terminal illness costs in all people who refuse euthanasia for various reasons, because it's unlikely that these peoples families will voluntarily cover the costs when there's the option that they don't have to.
Though I do see where you're coming from, and the last part is a good point. It'd certainly be abused that way, but that'd hardly be a first for a gov't-supplied service. That's part of why things with high abuse potentials are handled by the government, though; no private industry wants to touch them, and they're nearly guaranteed to lose money. As it's "for the greater good" though, it's worth the taxes (arguably).
I've seen some relatives die slow, lingering deaths and others fairly quick ones. Neither is ideal though it's bloody obvious which way is less unpleasant.
Enough time to tick off everything on your bucket list and properly say goodbye to those you care about is the best we can hope for.