I use
*{padding: 0; margin: 0;}
on all my CSS - various browsers have various default settings for various properties, and setting them all to 0 first and then adding the exact measurement you want later, prevents many cross-browser inconsistencies.
However, the opinions are divided - I find the above is simple and fast and takes care of everything at once, others belief it to be more efficient to only set to zero those properties that could be affected like so:
body, address, blockquote, dl, ol, ul, li, fieldset, form,
h1, h2, h3, h4, h5, h6, p, pre {
margin:0;
padding:0;
}