Experimenting with peppers

The past couple weeks I have been working on making the perfect chili using fresh peppers of various sorts. I got the idea when I was grocery shopping and I passed all the peppers. I don't really have a good idea how each kind tastes, so I wanted to figure out the heat and flavor. Since chili is one of the main foods I know that uses hot peppers, I have been making chili each week. The first batch I made included a Hungarian pepper and 2 jalapeño. It was not very spicy at all, but the flavor was good (I used 1 lb of ground beef and a can of black beans undrained, along with diced carrots, celery, onions, and cumin, cayenne pepper, and chili pepper). This week, I tried 2 jalapeño and 1 habanero pepper. It was super spicy--so spicy that I needed to add extra cheese to cut the heat a little. I think the habanero was a bit too much for us, so I will have to try a new type of pepper next time. If any of you have experimented with this, what types of peppers do you prefer and why?