What kind of sound machine do you have? Do you think the plain white noise or the actual sounds, like rain forest, ocean waves, etc, are better for baby? We live in the city, so some noise from outside is inevitable, plus our dog occasionally will bark kind of loud (not often, but could be jarring when it happens).

If you have one you love, please recommend it specifically! I know I want something I can have running all night, not a timed thing, given the random city noises and early morning barking fits from our neighbor's dog!