We all know and love the MSL services! Thank you NRIS and BMSC...

http://giscoordination.mt.gov/webservices.asp

http://nris.mt.gov/nsdi/orthophotos/raster_svc.asp

BUT WHAT ARE YOU USING?

Here is my short list:

ESRI Imagery: http://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer

BLM: http://www.blm.gov/nils/GeoComm/home_services.html

NWI: http://www.fws.gov/wetlands/Data/Web-Map-Services.html

USDA NAIP: http://www.fsa.usda.gov/FSA/apfoapparea=home&subject=maps&topic=gdw

BUT WHAT ARE YOU USING? PLEASE SHARE...