Is love a major theme in Romeo and Juliet? How much do you agree with this statement?

Yes, I would agree with the statement that love is a major theme of the play. When we first meet Juliet, her parents have just been approached by Paris, asking for their permission to woo her and, eventually, marry her. Juliet is not really interested in any ideas of love or marriage right now, but she hears her mother out. When we first meet Romeo, he is depressed as a result of his unrequited love for Rosaline. He certainly is uninterested in hearing about the possibility of loving anyone else at present.
And yet, at the Capulets' party, they fall in love with one another at first glance. Juliet goes from relatively passive to incredibly active, her love for Romeo spurring her on to make plans, send messengers, and eventually pretend to take her own life, leaving her entire family, so that she can be with him. Romeo, of course, becomes almost equally as active, arranging for their marriage, sneaking into her bedroom, and eventually taking his own life so that he can be with Juliet in death.  
If love is not a major theme of this play, then I don't know what is! (Of course, there are certainly other themes as well...)