Hotel Siddharta on Guest House Road is one of Mysore's reliable old-school vegetarian restaurants — a large, busy place with ceiling fans, formica tables, and a menu that runs through the full range of South Indian and North Indian vegetarian cooking. The masala dosa here are excellent: thin, crisp, and served with chutney and sambar that are remade fresh through the morning.
The midday thali is the best value meal in the city — a steel tray with rice, rasam, sambar, several vegetable dishes, papad, and buttermilk, refilled until you stop. Come early for breakfast (the restaurant fills by 8am) or at the beginning of the lunch hour (noon to 1pm) for the thali at its freshest. Prices are very low by any standard.