MapConnect has 1:250k data for download in many formats, including as ECW rasters which can be converted to GeoTiff with GDAL if needed. They also have a partial coverage of 1:50k topographic maps, but they cost money.
If you're interested in creating your own topographic maps, check out TopOSM, which aims to produce high-quality topographic maps from open data, and includes the source code to do so if you're willing to get your hands dirty. You might also find some hints in this quesion.
I don't know if it still works, but a couple of years ago I hacked together a method for downloading the US Seamless National Elevation Dataset in bulk that might work for topo raster maps too.
To bypass the map viewer put the
coords on the URL like so:
http://extract.cr.usgs.gov/Website/distreq/RequestSummary.jsp?AL=71.0,56.0,-140.0,-150.0&PL=NAK01HZ
where this is your region of interest
north,south and east,west in decimal
degrees.
AL=71.0,56.0,-140.0,-150.0
and this is data set to choose from,
in this case “National Elevation
Dataset Alaska (NED) 2 Arc Second”
PL=NAK01HZ
If you use this technique, please be gentle. It’s not in our interests to force them to take protective measures and close this avenue.
Also don't overlook snail mail, it's high latency but has almost limitless bandwidth:
With regard to ordering the regional
CD’s:
“You can order the entire U.S. in 30
meter resolution in either ArcGrid or
GridFloat format. The data will be
provided on a 250 GB external drive at
a total price of $1005.00. This
includes shipping and handling. This
will cover the Conterminous U.S.,
Alaska (at 60 meter res), Hawaii, and
the territorial islands. We no longer
provide this on CD or DVD media.”
An incredibly good price in my
opinion.
The contact address is
webmapping@usgs.gov
Customer Service/Webmapping
Data and Applications Support
Department Science Applications
International Corporation (SAIC) at
U.S. Geological Survey - EROS (Earth
Resources Observation and Science)
47914 252nd Street Sioux Falls, SD
57198-0001
Phone: 1-800-252-4547
Fax: (605)-594-6589
Best Answer
Carta topográfica escala 1:50 000
Three major scales are available: 1:1,000,000; 1:250,000 and 1:50,000.
The DRG maps in the scale of 1:50,000 are being issued and as of today (August 2008) about 85% of the country is available.. They have the same format characteristics as the 1:250,000 ones.
The 1:50,000 maps have shading to help in the terrain contour interpretation.
There are vector versions of these maps on both the 1:50,000 and 1:250,000 scales. For the 1:50,000 they are available for 60% of the country and for the 1:250,000 the whole territory is available.
The vertical divisions numbered 11 to 16 are the UTM zones in which Mexico lies.
http://www.bicimapas.com.mx/EnglishEdition/MexicanTopoMaps.htm
http://www.inegi.org.mx/geo/contenidos/topografia/default.aspx
http://www.inegi.org.mx/geo/contenidos/Topografia/Carta50000.aspx