I love thunderstorms or rain. That gets me to sleep in no time. That and no noise will get me to sleep. I used to have loads of problems getting to sleep but I started wearing earplugs and I sleep a lot easier now.
I hate birds singing when I'm trying to sleep. They are so annoying. We have a nest of birds in our back garden and they start tweeting at 12am and do not stop until the morning. Little ****ers used to keep me up for hours. I hated them.