India is home to one of the great vegetarian cuisines of the world. Be sure to obtain some spicy mango chutney and decent basmati rice.
Despite the impression you may receive from many Indian cookbooks, a huge variety of ingredients are not required for the preparation of some good, basic dishes. Some spices are essential (cumin, coriander, garam masala, chili powder, turmeric), as are some seeds (mustard seeds, whole cumin). Curry leaves are useful, and can be kept in the freezer. Out of the huge number of beans used in traditional Indian cooking, we stock chickpeas, red lentils, and brown lentils, and have learned to substitute these very effectively in all the dishes that we prepare.