For those of us just coming out of the typewriter age, here is a little update. Use only one space after a period. To take it even further, "Use only one space after periods, colons, exclamation points, question marks, quotation marks - any punctuation that separates two sentences". That is a quote from the book, "The Mac is Not a Typewriter". For everyone that thinks two spaces is okay should really check out this book. Also, if you are a designer, you need to read this. I am faced with this everyday and always have to make corrections. For anyone that disagrees with me, pick up any novel or book and look to see if it has double spaces. You will not find one. If that isn't evidence enough, visit www.press.uChicago.edu/Misc/Chicago/cmosfaq.