My horizontal nav appears vertical in IE 7. Here is the link to my test site: Inspired to Design. The nav is at the top (about, web, print, contact).

My nav css:

#nav {
	float: left;
	margin: -5.15em 0 0 30em;
}

#nav ul {
	list-style: none;
	position: relative;
}

#nav ul li {
	display: block;
	float: left;
	font-size: 1.2em;
	position: relative;
}
#nav ul li a {
	display: block;
	padding-left: 3em;
}
#nav ul li a:link, #nav ul li a:visited {
	color: #C6C;
	text-decoration: none;
}
#nav ul li a:hover, #nav ul li a:active, #nav ul li.selected a:link,
#nav ul li.selected a:visited {
	color: #6C6;
	text-decoration: none;
}

In a separate css style sheet with styles for IE7 only, I coded the following because I read that adding 'display: inline-block' and/or assigning a width to floated list items may solve the problem. I tried each style rule separately and then together. I also tried 'display: inline;'.

#nav ul li {
	display: inline-block;
	width: 10em;	
}

The result of the above code is the second two list items are vertically aligned under the top two list items with a lot of padding to the right of each list item.

I hope this is clear and detailed enough.