My favorite dressing is "Thaitalian Dressing."
It's made of Italian red wine vinegar (very important; not just red wine vinegar, it got to be italian red wine vinegar because taste differs so much. It can be made in the U.S.), fresh garlic (pressed), italian herb mix, extra virgin olive oil and Thai fish sauce. I usually have the vinegar, garlic and italian herb mixed in a bottle so that I can just add some oil and fish sauce. It's very tasty because of the fish sauce and garlic. Also, I add black pepper.
What's your original dressing?