There Is A Light definately or perhaps The Queen Is Dead.
Actually it's too f***ing hard to choose something like this! Never Had No One Ever, Bigmouth, Last Night I Dreamt.....,Shoplifters,That Joke Isn't Funny Anymore, Death Of A Disco Dancer,Rusholme Ruffians,I Want The One I Can't Have,Panic,Some Girls Are Bigger Than Others,Reel Around The Fountain,Girl Afraid, on and on!
I once did a presentation about Derek Jarman the artist/filmaker/writer/humanist
and showed the three proms for The Queen Is Dead. It was wonderful to have this film being shown to some of my classmates who'd never seen it and didn't know much about the Smiths, let alone Derek Jarman. It was funnt that other classes were interupted by the loud volumne at which I played it too!
Enjoy your assignment and add something about how his writing connects with you emotionally. Also, I think in general he's said that his writing is his life story and that's what you should tell them about his background/sexuality etc.
He also said it's like a dialogue with his fans!
It might be worthwhile mentioning how violent his shows can become. The audience has extreme love for him and he is very physically demonstrative as a perfromer. The audience can be physically demonstrative with him if they are lucky enough to jump on stage. I think his writing brings those feelings out in his audience and of course his amazingly beautiful and powerfull vocals.