Luke 24:1 states that today is the third day. And based on this one translation many have now excepted this to be the resurrection day on Sunday and have made this the reason they now keep Sunday as the Lord's Day and Easter Sunday. But is this a proper translation? Is there a reason for those doing the translation to change the wording ever so slightly?

The word today is not in the original Greek. It has been added. Lets look at this scripture and see the reason behind adding it to this passage and the motivation for doing it.
Music is Hallelujah to the Lord by Maranatha! Music, Messianic Praise Album