So much to like: Shakespeare inspired to steal the Doctor's quotations of him (and of Dylan Thomas); Shakespeare's flirting with Martha Jones--and the Doctor:
The Doctor: Come on! We can all have a good flirt later!
William Shakespeare: Is that a promise, Doctor?
The Doctor: Oooh, 57 academics just punched the air!
The use of Harry Potter's "Expelliarmus!" in the final defeat of the Carrionites.