I use a white noise machine with my 19 month old twins to drown out street noise and household noise. They have had night wakings since birth and on average I've gotten 3-5 hours sleep a night (I'm also a poor sleeper myself though). I would hate to take away the white noise and have them sleep worse.
That being said, if we were all getting good sleep I might try to get rid of the noise machine because of this study: http://www.webmd.com/content/article/63/72156.htm. Basically the study is says that rat pups who had continuous exposure to white noise had delays in the development in the hearing center of the brain. Extrapolated to human babies, some believe that white noise could cause hearing and language delays.
I get a lot of pressure to stop the white noise from my father-in-law who sent me the study. What takes away some of the worry for me is that my daughters don't have constant white noise, just at night. They are TV-Free, so during the day the only real noise is the music we put on to sing and dance with. Also, they seem to be experiencing typical language development - if there were delays I might be worrying more.