($100; amazon.com)
The priciest of our picks, the Sound + Sleep offers a good deal of versatility. It can actually detect other noises in your environment (say, the neighbor’s howling dog, or a snorer down the hall) and adjust to mask them. The gadget also has a unique “richness” feature, which allows you to add more detail to each of the 10 soundscapes (which include various nature settings, as well as options like “fireplace,” “trains,” and “city”). So for example, if you choose “ocean,” you’ll hear breaking waves. Touch the richness button to add in birds and seals. Touch it again and you’ll hear bells and foghorns. Other nifty extras: A headphone jack (in case your bedmate prefers to snooze in silence) and four auto-off timer choices (30, 60, 90, and 120 minutes).