A good free or paid theme for a eduction website?

Hello all, i have already asked some top memebrs what themes to use for a eduction site were users will login and teachers, once logged in they will be able to access data such as pdf's and videos that will be hosted from the site, and we need to collect user data emails names & address's if possible sw social docs looks good need more plugins free and paid no problem, would love some feedback and advice it will be really appreciated so much! 

The siter will be a free membership site, (a piad memebrship site will be built in 3 months)

i would rather have a paid theme but free is good to, having a paid theme would make the site more original and i am sure less sites use paid themes.

I look forward to any replies and advice links to products plugins themes and anything you think is relevant and will help me make a beautiful flawless and effective site. this site will have millions of users once it is live so i need to make sure it looks really good and is effective for the needs of the users.