I'm not a fan of tomato in chili, so I never put any actual tomatoes in. I might use a small can of sauce or some paste though.
IMO, essential ingredients in my chili are fresh peppers, both sweet and hot, onion, cilantro, garlic, beef (cubes or ground), and beans.
I also use lots of Penzey's chili powder, rehydrated dry ancho chiles, mexican oregano, additional cumin, unsweetened cocoa powder, salt, black pepper and a few secret additions.
I have won more than a few chili cookoffs with this recipe.