I like Lose It! It lets you look up calories for foods and has a barcode scanner for packaged foods. It has a food diary where you can keep track of what you're eating and an exercise log. You can also link some fitness trackers to it.
I really like MyFitnessPal, too. I really like that its homepage shows you your recommended daily calorie count as well as how many calories you've consumed that day. The homepage also shows how many calories you've burned that day with exercise. Most fitness trackers can sync with it, which is really helpful.