Suggested places to eat & drink in Darjeeling:

Cafe Coffee Day (Category: Mid-Scale)
Cuisine: Snacks & Coffee - you know the standard stuff they serve, it's no different here.
Location: On the Chowrasta Mall
Ambience: Large room with outdoor terrace seating with great views of the mountains.

Chanakya Restaurant (Category: Budget)
Cuisine: Bengali and other Indian dishes, Chinese
Location: DB Thapa Road, close to the taxi stand & Clock Tower. Part of Chanakya hotel.
Ambience: Large dining room with ordinary decor. Good views from the windows.