NOTE: Configuration -> Text formats (drag and drop to set priority of ordering)
Administer -> Site Configuration -> Input formats
Configure Filtered HTML (or create a whole new one that only applies to Blogs)
Then choose configure again
<a> <p> <span> <div> <h1> <h2> <h3> <h4> <h5> <h6> <img> <map> <area>
<hr> <br> <br /> <ul> <ol> <li> <dl> <dt> <dd> <table> <tr> <td> <em>
<b> <u> <i> <strong> <font> <del> <ins> <sub> <sup> <quote> <blockquote>
<pre> <address> <code> <cite> <embed> <object> <strike> <caption>
Filtered HTML not only strips disallowed tags, but also strips inline style definitions. That means that you are unable to apply different font color, size, family etc.