Since the professor is essentially doing you a favor, try to cover all bases by making this the simplest process for them. Also, the more information you give them, the better they get a sense for who you are...which is especially helpful if you have large classes and may not know your profs all that well.
A copy of your transcript will help your teacher get to know your performance as a student, and a resume with your school and extracurricular activities should be included. I had some questionable grades in some classes, but since i had included a list of my activities and jobs(and the avg # of hours spent doing each per week) listed by semester, it at least showed them that i was at least busy doing something rather than out partying my grades away.
You should also enclose a pre-addressed stamped envelope with the materials, and you also need to give a clearly stated date of submission for AADSAS or for the school. I gave a date that corresponded to the general time i was planning to submit my AADSAS app. Make sure to check back with them a couple weeks before the date to check on the status of the rec. (they may forget).
I also included which schools i was applying to in my letter of intent. I had a case where a professor felt that my letter of intent wasn't a broad enough sample of my writing ability, so he asked me for an additional writing sample. If you've worked on your personal statement, this would be a good place to add it, otherwise anything else that you're confident about should do.
