Dear Mr. Cook:
I want to thank you for meeting with me last week.
I realize how busy your
days are and appreciate your having made time to see me.
I would also like to
thank you for the insight you gave me into the world of entertainment.
You confirmed my belief that this business is where I should make my 
career.
Per your suggestion, I have accepted the internship in the Development
Department at Columbia Pictures.
I won't exactly be on the set, but I'll
certainly get a feel for what it takes to get a project off the ground.
Again, thank you for your advice.
I will certainly keep in touch to let you
know how things go.
Best regards