The USGS Seamless Data Distribution System is a good source for free data. The application allows for downloading of User specified US regions and selected layers for those regions. While the service is focused on United States Data, it does offer a limited selection of international layers as well.

How it works is as follows - you draw boundary around your region using one of the download tools and then select the layers you wish to download and then click the download button. For many requests the zip download file is available right on the screen without email. Tutorial available.