I keep a lot on hand. I buy a lot of dry foods in bulk then store everything in big plastic tubs. I figure it can also double as my emergency food supplies in the event of a disaster.
Fruit and Nuts:
almonds, walnuts, apples, bananas, medjool dates, seasonal fruits (I freeze a lot of the fruit so I can use it later in smoothies)
Beans:
red beans, black beans, lentils, split peas, textured vegetable protein
Grains & flours
Couscous, brown rice, quinoa, amaranth, barley, white flour, whole wheat flour, bread crumbs, oat bran, oatmeal, corn meal, whole wheat spaghetti, popcorn, garbanzo bean flour (for making hummus)
Seasonings:
Paprika, cayenne, crushed red pepper, garlic powder, onion powder, chili powder, chipolte, cumin, black pepper, oregano, basil, cinnamon, unsweetened cocoa powder
Oils:
Extra virgin olive oil, canola oil, Earth Balance
Other stuff
Unsweetened soy milk, tofu, maple syrup, vanilla extract, yeast, baking powder, Ener-G egg replacer, natural peanut butter, canned unsalted tomato sauce, onions, garlic
I would say the most frequently used items are the garlic, onions, olive oil and crushed red peppers. They end up in a lot meals.
Vegan Cookbooks Illustrated
http://vegan-cookbooks-illustrated.blogspot.com/
http://pinterest.com/VeganCookbooks/