I personally prefer canned tomatoes unless I can get tomatoes that are actually ripe. Most of the time I find store bought fresh tomatoes to be rather bland.
The hubby and I make several different chilis (well, actually, he makes his and I make his and a couple others). Some of our favorite ingredients (besides tomatoes) include celery (preferably with the leaves), onion, green onion, garlic cloves, green pepper, Anaheim chilis, serranos, jalepeños, pablanos, cherry peppers, hungarian yellow peppers, habeñeros, light and dark red kidney beans, cilantro, corriander, cumin, chili powder/ground dried chilis, allspice, lime juice and apple cidar vinegar.
We frequently use a mix of chilis. We find it adds depth to the flavor We always add the onion, garlic, corriander, cumin, chili powder and allspice. We usually add the celery and either green pepper or pablanos. When I use the lime juice I add it to the meat while it's cooking and don't use the cider vinegar. When I use the cider vinegar I add it toward the end of the cooking process and don't use the lime. We try to keep the beef and chilis the main flavor, the spices an aromatic, well blended second, and anything else there as accents.