I would not use a <div> where a <p> should go. If I need to change how the <p> performs, I'll use a class for that. For <p>, I set it in CSS to be as I will most use it. I rather dislike <p class="indent"> in most <p> when just <p> will do. My <p> CSS sets the indent and the margins.
Code:
body {
widows: 1;
orphans: 1;
margin-top: 0;
margin-bottom: 0;
margin-left: 0;
margin-right: 0;
text-align: justify;
}
p {
margin-top: 0;
margin-bottom: 0;
text-indent: 1.2em
}
That works for most <p> in a book and it looks good.