What material should I bring to my first meeting/interview with my prospective advisor? During a very brief email exchange, a professor of my university (mathematician) said that he is available to take on a masters student at the moment and gave me an appointment during his office hours.

Roughly in the same spirit as the question How much detail to include in first email to potential PhD supervisor?, I'd like to ask 


  What kind of "support material" should I bring to this "interview" to make sure the professor collects a sufficient (and sufficiently well-organized) amount of information?


I mean, in addition to the basics, which are


a copy of my CV;
a copy of my trascript;
a concise summary of my mathematical background that is relevant to the (possible) thesis topic with precise references to courses, workshops, conferences, summer schools, and the books or papers I've read.
It looks like you're set with respect to material things. What I would encourage you to prepare is an agenda -- which, in this case, means a set of immediately practical questions you need answers to, and one or two conversation-starters regarding your would-be advisor's research and that of his existing advisees.

Practical questions: what paperwork is involved in formalizing the arrangement, when should you report to start work, that sort of thing.

Conversation starters: "I read your recent 'Mathematical Models of Baskets' in the Journal of Underwater Basketweaving; are you still working on that?" "What are your current students working on, and is there anything you wish somebody would tackle?" and that sort of thing.