There has been considerable gnashing of teeth at my school over student use of Wikipedia. Some of our teachers absolutely forbid its use, only to have that be the student's first choice in research tools. I, personally, think that it should be used and that teachers ought to be using it to teach information literacy, but that's just me.
One research application that I have found draws its information from Wikipedia. EyePlorer is a visual reference tool that allows you to set your search term and then it displays related terms in a circle around your original term. Hover over one of the related terms and information from Wikipedia about that term will pop up. You can then drag the information to your EyePlorer notebook page and save the results of your search.
I think this tool would be a very useful starting point for students, especially younger ones, doing research papers or reports. All too often, students start with very broad categories or terms and get frustrated because they get several million hits in their search engines. Here, they can see what topics to use to narrow their search, and they can save their information. I can't wait to see some of our students using it!