[SusanM]

I am just testing out InDesign CS6 and it automatically includes a streamlined CSS reset when exported to ePub. This is the code:

body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, p, pre, code, blockquote {
margin:0;
padding:0;
border-width:0;
}
td, th {
border-style:solid;
border-width:1px;
}
table {
border-collapse:collapse;
}
li {
display:block;
}

I have also seen this reset code in ePubs:

html, body, div, span, object, iframe, h1, h2, h3, h4, h5, h6,
p, blockquote, ol, ul, li, pre, a, cite, code, del,
dfn, em, font, img, q, s, samp, small, strike, strong, sub,
sup, tt, var, b, u, i, center, dl, dt, table, caption, tbody, tfoot, thead, tr, th, td {
margin: 0;
padding: 0;
border: 0;
outline: 0;
font-size: 100%;
vertical-align: baseline;
background: transparent; }

Yes, it doesn't work on all readers (engines), but it does make a difference on quite a few, especially if you start using background images on headers, etc. and use the second example. My view is it makes the "playing field" more predictable!