Speaking of quads, the USDA has a site <a href="http://datagateway.nrcs.usda.gov/">http://datagateway.nrcs.usda.gov/</a> where you can download countywide mosaics of USGS 7.5' quads in MrSID. Saves a lot of work getting and compiling quads, especially as they include quads that have even a little bit in the county he is mosaicked, so you do not often need to download both counties when your feature of interest tends to follow county lines.