I totally agree with you about 'The Social Network.' What an incredible film. I've seen it three times now and it just keeps getting better. A modern American masterpiece in my eyes :-)
I must confess I have a major boner for Peter Sellers as Quilty.
I hate to admit it but I've only seen one Tarkovsky film so far, and that would be Solaris. After I check out more of his, I'm sure I'll add them to the list.