I always admired the way in which Shakespeare created the structural climax of this play in Act 3, scene 1. It's amazing how the circumstances of the play go from being so joyous (Romeo and Juliet are married between Acts 2 and 3) to so tragic (Tybalt kills Mercutio and Romeo kills Tybalt) in such a short period of time. It's obviously a sad turn of events, but sadness is what makes so many of Shakespeare's plays so wonderful.
I would have to agree that the balcony scene seems an easy (almost cliche) choice here. However, in my mind, no other scene from this play better captures the power, skills, and allure of Shakespeare. We see the use of irony, contrasts, figurative language, pun, etc. all expertly woven together to express one of the most elemental human experiences in a way most readers find captivating, fresh, and unique regardless of how far removed they may be from the scene's writing.
For the reader who has appreciation of the poetic nature of Romeo and Juliet, there is no better passage than Act II, Scene 2 in its beautiful light/dark imagery:
How many are not familiar with these lines?
But soft! What light through yonder window breaks?
It is the east, and Juliet is the sun!'Arise, fair sun, and kill the envious moon,
Who is already sick and pale with grief
That thou her maid art far more fair than she.
And, how quintessentially romantic are these lines?
See how she leans her cheek upon her hand!
Oh, that I were a glove upon that hand
That I might touch that cheek.
My favorite without a doubt is Act II, Scene 4. I think it is the immature male in me, but all the bad puns (many of which are sexual) really make me laugh. I also remember them fondly because we threw them in the face of my 12th Grade English teacher who criticized us for being crude and crass in comparison to the cultured people of Shakespeare's day.
With Romeo and Juliet you have three options: humor, action, or romance.
Which do you like the best?
Humor: (Almost any scene with the nurse or Mercutio - but I also think it is pretty funny when the Friar tells Romeo he's acting like a woman.)
Act 1, Scene 1
Act 2, Scene 5
Action: (All the sword fighting and death scenes.)
Act 1, Scene 1
Act 3, Scene 1
Romance: (The original meeting and then of course the most famous balcony scene.)
Act 1, Scene 5
Act 2, Scene 1
Romeo and Juliet is at its best when Mercutio is on stage. He steals the show in nearly every scene he's in. Although his Queen Mab speech is a tempting pick, his death scene is not only the best in the play but a dramatic turning point in the plot.
Mercutio does it all in Act III.i: he waxes philosophical, he picks a fight with Tybalt, he swordfights, and he dies giving one of the most famous death scene monologues ever. Even in death, he is funny and tragic:
No, 'tis not so deep as a well, nor so wide as a
church-door; but 'tis enough,'twill serve: ask for
me to-morrow, and you shall find me a grave man. I
am peppered, I warrant, for this world. A plague o'
both your houses! 'Zounds, a dog, a rat, a mouse, a
cat, to scratch a man to death! a braggart, a
rogue, a villain, that fights by the book of
arithmetic! Why the devil came you between us? I
was hurt under your arm.
His cursing of the two houses is something like an Oracle from Greek tragedy. Not only does he foreshadow the tragedy to come for the lovers, but he incites Romeo's revenge which, in turn, leads to exile and eventual suicide.
There are two battles in this scene: Mercutio vs. Tybalt and Romeo vs. Tybalt. The verbal and physical action are both fierce, easily making this the most pivotal and best scene in the play.
I suggest you look at the play's opening, Act I scene 1. This is the first time we see the conflict between the two houses, Montague and Capulet. The men involved are throwing insults at one another with surprising wit and intelligence. "Do you bite your thumb sir?" starts the quarrel, but the wordplay that goes back and forth between the groups takes this question in many directions. If you have a good copy of the play you can usually look at the text's notes to learn all the puns and double meanings that make the sense both tense and hilarious. This scene is quick and energetic. It does a fabulous job of setting the tone for the rest of the drama!