I would go to this website for some ideas: http://www.best-speech-topics.com/good-i…
I recently finished a public speaking course this past spring. My teacher said that the informative speech is like an "information dump" where you don't share your opinions, so controversial topics (as you stated above) don't work very well.
One of the most importaint things to remember about this is to have fun, and do something that YOU enjoy.
For instance, i am a history major, and so i decided to do my informative speech on the holocaust- primarily life in concentration camps. Other people in my class did topics such as: topics about different animals (macaws, endangered species), research about how different companies or organizations were founded, different scientific theories, and i must say the most popular were historical facts (like wars, or even biographies).
Again have fun, and don't pick a topic that you are going to DREAD looking up. =)