When I first began basing my figures, I was using plain sand and painting it to look like dirt. This really went against my model railroading senses. Then I switched to Woodland Scenic ballast and talus for my bases, applying the ballast to the base without any painting. The process was faster than painting sand, and I like the results! WS's shades of browns look good for games set in the Eastern US or Europe. Unfortunately, they don't look so good for games set out West. Knowing this, I dragged my feet all summer when it came to basing my finished 25mm Western figures.
A few weeks ago, I picked up a couple bags of ground rocks from Arizona Rock & Mineral Company. After comparing many different colors in person at the local hobby shop, I settled for their Cajon bags in the picture. The color is meant to match the ground color of Santa Fe's Cajon Pass east of LA. Having visited the area years ago to photograph trains, I felt this looked suitable for a generic Western game. The Sand & Gravel bag has textures ranging from fine powder to larger bits. The Rip Rap will be for those occasional large stones.
Check their website. They have some great products, especially if you want to do adobe houses in a deep brownish red color. Good stuff!