I spent a year on the Texas/Mexico border and really grew to enjoy a very basic salsa:
Diced fresh tomato (be sure to include the juice)
Diced onion (my preference being Vidalia)
Diced fresh pepper (my choice is a mix of poblano and jalapeño - I stay away from the habaneros)
Salt to taste
Splash of lime juice (optional)
Splash of tobacco (usually the green or chipotle)
Amount of each ingredient is usually based on taste and what I have on hand.
My other favorite is roasted salsa. We would sometimes make it over mesquite coals at my friend’s ranch. Ingredients are basically the same, but we would roast the peppers, tomatoes and onion over the fire before chopping up or putting in a blender for the salsa.
And don't forget the guacamole! Just mix/crush the avocado with some onion, tomato, lime juice and salt to taste.