I'm iffy on the death penalty. In the US, many people have gotten off death row because they were shown to be innocent. You can't take back an execution. Secondly, it's grossly unfair - minorities and poor people who commit the same crimes get the death penalty much more often than other people.
I think if the case is absolutely clear cut (DNA evidence, direct video tape, etc) and it was applied fairly regardless of socioeconomic background, I might be for it. But that's a very idealized situation that occurs rarely enough as to be not worth even having it on the books, in my opinion.