Just my two cents, but I don't use a lot of pure superhot powders. I usually blend onion powder, garlic powder, salt, sugar, and other herbs and/or spices (mustard, ginger, thyme, oregano, cumin, coriander, cardamom, dehydrated coconut milk...the list is endless, it's just about which flavors go well together). To that, I add one blend or another chosen for both heat and flavor. I'm partial to both the St. Lucia Red and Grenada Yellow Seasoning Peppers, as well as most of the baccatums, for flavor. To bring some heat, I like Giant White Habaneros (actually a lot hotter than any garden variety hab I've ever had), Moruga Scorpions, Yellow Brainstrains, and a Peach Bhut selection I've been working on. Two pieces of advice: set your dehydrator at 100 degrees or so, which will preserve the color of your pods, and consider smoking some of them before you dehydrate. Adds a really nice depth to your finished powder.
Oh yeah, and MoA scotch bonnets are great.