It's "thou shalt not murder,"
It's actually Hebrew that Slashdot won't reproduce, and the translation is normally held to be "Thou shalt not kill" on the basis that is what the KJV translates it as. Other more modern translations use "kill" rather than "murder". Nice selective translation, though.
No, the translation is not "normally" held to be "... kill." Especially not because of the KJV. The modern English translations, including the most popular ones, translate the word as "murder". See, for example, the New International Version, the New American Standard, the Amplified Bible, even the New King James Version. Also, an old, but literal translation, the aptly-named Young's Literal Translation, translates it as "Thou dost not murder." Take a look at the other translations on that site and note how the vast majority translate the word as "murder." Pretty much the only modern, widely-used, translation that uses "kill" is the New Jerusalem Bible.
And FYI, the "Hebrew that Slashdot won't reproduce" can be romanized as "rasah", a term that while hard to pin down the exact meaning of, scholars generally agree means more than simply "kill". This site has some discussion of it.
It's also notable that the Bible explicitly mentions the death penalty as acceptable: "Anyone who kills a person is to be put to death as a murderer only on the testimony of witnesses. But no one is to be put to death on the testimony of only one witness." -- Numbers 35:30. So perhaps that will refresh the memory of the AC a few posts up who "[didn't] recall any exceptions for "Oh but if the other guy killed someone else that's O.K, you know?"