Guacomole! When I'm behaving this is my goto dip or condiment (great on dogs, burgers etc...). Key is using the properly ripened avocado. You want the avocado to be not quite firm. (If it's firm it's almost inedible, if it's too ripe it will be too squishy) When you mash them (don't use a food processor or blender, a potatoes masher or similar, even a large fork is best) don't overmash, leave some soft chunks for texture.
When seeding the tomatoes make sure to discard the juicy parts. You want the firm flesh (again this is to keep the texture more of a thick dip, don't want runny).
Lime must be fresh, and add a little zest of the lime too (careful not to get much of the pith(white part).
If you don't like cilantro try fresh parsley.
The above are my extra comments below is the recipe from Alton Brown and original URL. I got this originally off his TV show, back when the Food Network had cooking shows :/
3 Hass avocadoes, halved, seeded and peeled (or 4 small ones)
1 lime, juice of
1/2 teaspoon kosher salt
1/2 teaspoon ground cumin
1/2 teaspoon cayenne
1/2 medium onion, diced
2 roma tomatoes, seeded and diced
1 tablespoon cilantro, chopped
1 garlic clove, minced
1 Wash and prepare produce.
2 Put avocado innards and lime juice into a large bowl, toss to coat.
3 Add salt, cumin, and cayenne, and mash with a potato masher or whatever you can find to mash it with.
4 Fold in onions, tomatoes, cilantro, and garlic.
5 Let sit at room temp temperature for an hour, then serve.