1 - you can add a specific class to accomplish this, then wrap the boxes with the class
Say:
.forumlinks A:link {
text-decoration: underline;
}
.forumlinks A:visited {
text-decoration: underline;
}
.forumlinks A:active {
text-decoration: underline;
}
.forumlinks A:HOVER {
text-decoration: underline;
}
2. are you adjusting the text size? You could handle it the same way, add a class, then set font-size to the size you prefer.
3. you can adjust cellpadding in your theme settings up one pixel and see if it's better. If you don't like the way it loks throughout, you can adjust that particular table in the postlist.tmpl
