Hey, don't knock graphic novel versions. They can be both fun and educational as far as presenting the core of the story and "best-known scenes" goes. The new manga versions of Shakespeare are especially cracktastic.
But yes, it's best to use adaptations as supplements to the actual text.
However, the actual text can be a bit overwhelming for people who haven't gotten into Shakespeare before, and so adapted versions in any media can be a nice lead-in to people genuinely understanding and enjoying the plays, rather than finding them just another imposed-upon curriculum chore that they don't "get".
And stuff like Akira Kurosawa's
Ran and
Throne of Blood, the Ian McKellan version of
Richard III, Julie Taymor's
Titus and
Romeo + Juliet and
10 Things I Hate About You kind of show the universal applicability of certain of Shakespeare's stories by taking them well out of their regular stage setting and "period" context. A lesson to be learned in that, I think.
Anyway I think I'll leave* with a mention of Connie Willis' hilarious short story
Ado, which shows the other things that can go wrong when one tries to teach Shakespeare in the future.
* Tempted to say "exit, pursued by a bear", but I've already done that twice this week.