If the only source you're going to be using is a standard definition DVD, then save your money and go with the 720p projector as it can show every detail of your standard def DVD's. Sure there would be a difference if you were using 1080p material from HD-DVD or Blu-ray or 1080i material from a broadcast, but if not, then it would be silly to spend the extra $ on something that you would not utilize (higher resolution). Now if the more expensive project has other aspects that make it better (light output, contrast ratio, specific inputs that the other doesn't...) then there would be different things to consider in choosing between the two units, but for what you're telling us so far, just for resolution comparison, save your money if you're going to use regular DVD's only and go 720p.