With the many different types of Chillies in this world, it may be difficult to decide which one to use in your cooking with Chillies. How do you go about choosing? There is no hard and fast rule in this regard, but some general principles apply. For example, if you have a local or national Chilli that is traditionally used in recipes in your country, obviously, go with that. If you cannot get hold of a particular Chilli specified in a recipe, use a substitute. For example, the Habanero can easily be substituted by Scotch Bonnets, Thai Birds-eye Chillies by African devils and Hildagos by Serranos. At the end of the day, these Chillies are distant relations to each other anyway, and substituting one for the other won't make much difference to your final dish.
The Chillies below represent the ones you are more likely to find in stores. Each variety mentioned can be used as a substitute for other Chillies, which will help if you find yourself stuck.