Some relates Q&A's from a math student discussion group: http://mathoverflow.net/questions/28158/a-learning-roadmap-request-from-high-school-to-mid-undergraduate-studies http://mathoverflow.net/questions/1812/learning-new-mathematics http://mathoverflow.net/questions/28438/mathematics-and-autodidactism http://mathoverflow.net/questions/4580/pacing-for-learning-new-material
This is a good starting point for generally useful math. Probability is a conspicuous omission.
http://www.reddit.com/r/math/comments/eohrr/to_everyone_who_posts_about_learning_more_math/