We use white noise at home religiously! We sleep with it during naps, at night and sometimes driving in the car. I am not worried about it at all! I am glad to have something to help soothe my DS to sleep with. I know he has developed a sleep association with it and that is OK by me!
I read the article above about the study, and I am still not concerned one bit. I'd need a lot more data from multiple sources to convince me that the study was significant in any way. Also, my baby is not a rat, does not think like a rat, and does not have the same developmental needs and issues as a rat in a cage.... so I'm not buying it!
After watching Dr. Karp's "Happiest Baby on the Block" DVD, I started using traditional white noise (static sound) when I needed to soothe DS as an infant. That gradually changed to a "raindrop on the roof" noise that we now use ALL THE TIME! I started using it for the same reason as you... to drown out noise from outside of the room, while he was napping or before we went to bed (as our main living space is right outside the door).
The bottom line is it helps to soothe him, he associates it with a sleepy state, and he is developing an understanding of how to get settled and sleep on his own (eventually!
). I totally advocate it for those who are struggling to get their DC to sleep better!
We co-sleep and thankfully DH doesn't mind it at all. It used to drive me bonkers, but in time I was finding it helpful to wind down too. Most nights it is on all night (becuase I fall asleep before I can turn it of). When we are nursing to sleep the volume level depends on DS's mood. If he is really fussy and having a hard time going to sleep, the volume is high (I can tell that it has a calming effect on him). As he nods off, I lower it and lower it a bit again when he is asleep.
Oh! Sorry for the loooooooooong response!