Personally I believe Voldemort should die as punishment for what he has done, but killing him would make us just as bad as he is. If we gave him a taste of his own medicine then we would be lowered to his same level of evil and scum.
I don't believe in the whole "Good and Evil" thing, if anyone is offended by that I apologize ahead of time. Meaning I could not just kill Voldemort because he was an evil feeling-less person. People on act on what they believe is right or what they think would be best for them. As a child Tom Riddle did not exactly have the best upbringing and was not shown love, he is an emotional needy and attention hungry child who wants to punish others for the pain and hurt he had to endure.( I think that is one of the reasons) Voldemort is prejudice to muggles, not just because he feels like hating people but for a reason. His father was a muggle and did not love nor care for him,( he obviously took revenge on him for this) and he was placed in an orphanage with other muggles that probably treated him badly. Tom was a selfish child possibly due to the fact he had nothing, so to make up for that he took other's possessions even if it hurt them. In his mind hurting others to gain something for yourself was okay, since he did not care for them nor did they him. Due to this conditions I believe Voldemort hates Muggles for this reason. This was just one of my theories on why Voldemort acts the way he does.
Although Voldemort's actions are justified to himself, that still does not excuse them. He knew what he was doing was angainst the laws...so it was not like he did not know. I don't know about wizarding laws, but he is a danger no matter where he is and killing him would be one sacrifice to save millions. On that level it would only be fair to save millions instead of one.....
I hope this made sense!
~Lady Black~