One thing that can be frustrating at times, though, is entering in all the stuff I've eaten. Especially if it's not in the database or it's not something I'm going to eat often enough to worry about putting in. For those instances, I have a hack - zGeneric10 and zGeneric100 - these are items for which each serving is 10 or 100 calories, respectively. So when I know the size of something but I don't really care to get specific, I just use the required number of servings (a 425 calorie entree becomes 42-1/2 servings of zGeneric10.) Helps me stay on track, but save time.
You'll also notice "zCoffee" and "zCreamer30," two other items I enter on a fairly regular basis. Coffee Mate (and Fred Meyer and other generic) offer some very good low-fat creamers (French Vanilla and Hazelnut are the most commonly available ones).