I strongly encourage looking for filmed stage productions, particularly--though not only--when sharing them with students. Not only is stage Shakespeare's medium, but young people tend not to be very aware of the theater and exposing them to a stage production can open an entire new world for them.
The Globe Theater has released a good
Othello on DVD. This would give students a sense of the theater in which the play was originally performed.
http://www.google.com/products/catal...d=0CJQBEPMCMAg
The closest thing to a filmed stage production of
Macbeth I'm aware of is a DVD usually sold as
A Performance of Macbeth. In 1979 (I think), Trevor Nunn directed a famous and influential staging of the play starring Ian McKellen and Judi Dench, which he later filmed. It's sort of a cross between a film and a recording of the production. Very strong performances.