Wiri wiri, thai/bird's eye chilis, jalapeno, habanero...
Perhaps ultimately there will be individual threads for favorite pepper species, but for now, let's start with a big thread of delicious hot pepper varieties that grow in hot climates!
My neighbors are growing scotch bonnets in buckets, with such flourishing success that I have no need to ever try to grow any myself!
I have not grown any hot peppers since the first year I moved here, because they all got such a terrible attack of whitefly it didn't seem worth it. But I am more on top of things now, and am considering trying a few varieties again. I wonder if they can grow in the poor soil here, or if they can only grow in containers - neither myself nor my neighbor has ever tried them in-ground yet. I am more partial to Thai red varieties, than the harsh bite of most Caribbean peppers I've tried. But I think I'm ready to try a variety of them and just see how they all do. I'd prefer anything that can just grow in my soil and doesn't need a ton of care at this point, and can handle our scorching summers, drowning wet season, and parched dry season (or at least one of those!).
I found this to be a really fun article on India's love for chili peppers:
http://economictimes.indiatimes.com/magazines/et-magazine/indian-chilli-displacing-jalapenos-in-global-cuisine/articleshow/8190311.cms