With the recent Nov. 1, 2011 change in the seamless.usgs.gov server, I am having trouble finding the equivalent USGS site to work with adjacent quadrangle TOPOs in order to make a seamless raster map that covers part of two adjacent USGS quads. I have tried the suggested sites (nationalatlas.gov, earthexplorer.usgs.gov, and nationalmap.gov), but haven't had any luck. I can download a single quad, but haven't been able to specify adjacent quads to make a custom raster map using G-raster. I used USAPhotoMaps to download adjacent quads, but these are jpegs, and wanted to compare the same area using geotiff files, which supposedly might be a bit better, according to Leszick P. Any ideas??
http://data.geocomm.com/
Has DEMs by quad name, also DRGs and DLGs by quad name. You'd need software to combine them though.
I use Globalmapper to download USGS DOQ's from MSRMaps.com. Has always seemed easier than the seamless site to me. Unfortunately that won't help if you don't have Globalmapper though.