Wikipedia in French, and Wikipedia in German are very good. They have each of them the third of the articles of the English Wikipedia (in 2012, source: http://royal.pingdom.com/2012/06/13/the-biggest-and-busiest-... ). Note also that the German Wikipedia had as many edits as the English ones, with fewer articles, which could be a good indicator of the (good) quality of the German Wikipedia.

More generally, there are plenty of very high quality websites in other languages than English on the Internet.