Manali market is key place for eatables. Right from chat to Indian (veg/nonveg) to international cuisine like Italian/Chinese are available in the main market which is just opposite the Manali Bus stand. The mall road has a variety of eating options ranging from stalls and dhabas to fancy restaurants. Deeper into the lanes of the town, one can find more local eating places, catering to special tastes and habits ranging from Tibetan food, to Vaishnavi Dhabhas. You are sure to find something without hunting around too much.
Old Manali is one of the best places to hang out in the evening. It has a great collection of restaurants/bars and shops. It is also not crowded like the Mall Road, with the crowd consisting mostly of foreigners.