I encourage everyone (and challenge anyone who believes in evolution) to read "How Evolution Flunked The Science Test". Here's the link: http://www.nisbett.com/library/how_evolution_flunked_the_scienc.htm
I agree, the day does matter. What's important to God should be important to us. God wrote the 10 commandments with His own finger in stone. He wants us to keep Saturday holy, not a day of our choosing such as what the Catholic church instituted with Sunday observance.