There are some people in this world who just cannot live without anything that is not spicy. If you would check out the different chili peppers, you will come across two namely the poblano pepper and the jalapeno pepper.
Between the two, the jalapeno pepper is said to be spicier although it is not as spicy when you would compare it to the other types of pepper. The range of spice of the poblano pepper is 1000 to 1500 SHU while the Jalapeno pepper will be two to eight times spicier than that.
It would depend on where you will get your chilies. Take note that it is not advisable that you will eat chilies that are more than what you can handle. Some people have made some holes in their gut just because of trying to eat the spiciest chili that they can find.