feeling like an idiot - multiple issues

[gjh42]

Your main problem is that you have extra padding and other height-producing code in your stylesheet. You also have a huge amount of redundant or useless properties in there, like the
margin-left: auto;
margin-right: auto;
all over the place. Your stylesheet will be easier to understand and edit if you remove those. Part of your current stylesheet:

/*wrappers - page or section containers*/
#mainWrapper {
	text-align: left;
	color: white;
	width: 647px;
	vertical-align: top;
	background-color: #000000;
	background-position: 50% 50%;
	margin-left: auto;
	margin-right: auto;
	}

#headerWrapper, #logoWrapper, #cartBoxListWrapper, #ezPageBoxList, #cartBoxListWrapper ul, #ezPageBoxList ul, #mainWrapper, #popupAdditionalImage, #popupImage {
	margin: 0em;
	padding: 0em;
	background-color: #000000;
	text-align: center;
	margin-left: auto;
	margin-right: auto;
	}
	
#contentMainWrapper {
	margin: 0em;
	padding: 0em;
	background: url(http://www.evilbrandclothes.com/img/body.jpg);
	vertical-align: top;
	background-position: top center;
	width: 647px;
	text-align: left;
	margin-left: auto;
	margin-right: auto;
	}

#navColumnOneWrapper, #navColumnTwoWrapper, #mainWrapper {
	margin: auto;
	margin-left: auto;
	margin-right: auto;
	} 

#tagline {
	color: #000000;
	font-size: 2em;
	text-align : center;
	vertical-align: middle;
	}

#sendSpendWrapper {
	border: 1px solid #cacaca;
	float: right;
	margin: 0em 0em 1em 1em;
	}

.floatingBox, #accountLinksWrapper, #sendSpendWrapper, #checkoutShipto, #checkoutBillto, #navEZPagesTOCWrapper {
	margin-left: auto;
	margin-right: auto;
	width: 47%;
	}

.wrapperAttribsOptions {
	margin: 0.3em 0em;
	}

/*navigation*/

.navSplitPagesResult {}
.navSplitPagesLinks {}
.navNextPrevCounter {
	margin-left: auto;
	margin-right: auto;
	font-size: 0.9em;
	}
.navNextPrevList {
	display: inline;
	white-space: nowrap;
	margin-left: auto;
	margin-right: auto;
	padding:  0.5em 0em;
	list-style-type: none;
	}

#navMainWrapper, #navSuppWrapper, #navCatTabsWrapper {
	margin-left: auto;
	margin-right: auto;
	background-color: ;
	font-weight: bold;
	color: #ffffff;
	height: 1%;
	width: 647px;
	text-align: center;
	}

#navMain ul, #navSupp ul, #navCatTabs ul  {
	margin-left: auto;
	margin-right: auto;
	padding:  0.5em 0em;
	list-style-type: none;
	text-align: center;
	line-height: 1.5em;
	}

#navMain ul li, #navSupp ul li, #navCatTabs ul li {
	margin-left: auto;
	margin-right: auto;
	display: inline;
	}

#navMain ul li a, #navSupp ul li a, #navCatTabs ul li a {
	text-decoration: none;
	padding: 0em 0.5em;
	margin: 0;
	color: #ffffff;
	white-space: nowrap;
	margin-left: auto;
	margin-right: auto;
	}

#navEZPagesTOCWrapper {
	font-weight: bold;
	float: right;
	height: 1%;
	border: 1px solid #000000;
	margin-left: auto;
	margin-right: auto;
	}

#navEZPagesTOC ul {
	margin-left: auto;
	margin-right: auto;
	padding:  0.5em 0em;
	list-style-type: none;
	line-height: 1.5em;
	}

#navEZPagesTOC ul li {
	white-space: nowrap;
	margin-left: auto;
	margin-right: auto;
	}

#navEZPagesTOC ul li a {
	padding: 0em 0.5em;
	margin-left: auto;
	margin-right: auto;
	}

#navCategoryIcon, .buttonRow, #indexProductListCatDescription {
	margin-left: auto;
	margin-right: auto;
	}

#navMainSearch {
	float: right;
	margin-left: auto;
	margin-right: auto;
	}

#navBreadCrumb {
	background-color: #cc9900;
	margin-left: auto;
	margin-right: auto;
	}

#navEZPagesTop {
	background-color: #ffff33;
	margin-left: auto;
	margin-right: auto;
	}

#navBreadCrumb, #navEZPagesTop {
	font-size: 0.95em;
	font-weight: bold;
	margin: 0em;
	padding: 0.5em;
	}

#navColumnOne {
	}

#navColumnTwo {
	}

Edited to remove superfluous properties with no change in output, except for the noted edits to tighten up spacing:

/*wrappers - page or section containers*/
#mainWrapper {
	text-align: left;
	color: white;
	width: 647px;
	vertical-align: top;
	background-color: #000000;
	}

#headerWrapper, #logoWrapper, #cartBoxListWrapper, #ezPageBoxList, #cartBoxListWrapper ul, #ezPageBoxList ul, #mainWrapper, #popupAdditionalImage, #popupImage {
	margin: 0em;
	padding: 0em;
	text-align: center;
	}
	
#contentMainWrapper {
	background: url(http://www.evilbrandclothes.com/img/body.jpg);
	vertical-align: top;
	background-position: top center;
	width: 647px;
	text-align: left;
	}

#navColumnOneWrapper, #navColumnTwoWrapper, #mainWrapper {
	margin: auto;
	} 

#tagline {
	color: #000000;
	font-size: 2em;
	text-align : center;
	vertical-align: middle;
	}

#sendSpendWrapper {
	border: 1px solid #cacaca;
	float: right;
	margin: 0em 0em 1em 1em;
	}

.floatingBox, #accountLinksWrapper, #sendSpendWrapper, #checkoutShipto, #checkoutBillto, #navEZPagesTOCWrapper {
	margin-left: auto;
	margin-right: auto;
	width: 47%;
	}

.wrapperAttribsOptions {
	margin: 0.3em 0em;
	}

/*navigation*/

.navSplitPagesResult {}
.navSplitPagesLinks {}
.navNextPrevCounter {
	font-size: 0.9em;
	}
.navNextPrevList {
	display: inline;
	white-space: nowrap;
	padding:  0.5em 0em;
	list-style-type: none;
	}

#navMainWrapper, #navSuppWrapper, #navCatTabsWrapper {
	font-weight: bold;
	height: 1%;
	text-align: center;
	}

#navMain ul, #navSupp ul, #navCatTabs ul  {
	padding:  0em 0em; /*change to tighten up*/
	list-style-type: none;
	text-align: center;
	line-height: 1.0em; /*change to tighten up*/
	}

#navMain ul li, #navSupp ul li, #navCatTabs ul li {
	display: inline;
	}

#navMain ul li a, #navSupp ul li a, #navCatTabs ul li a {
	text-decoration: none;
	padding: 0em 0.5em;
	margin: 0;
	color: #ffffff;
	white-space: nowrap;
	}

#navEZPagesTOCWrapper {
	font-weight: bold;
	float: right;
	height: 1%;
	border: 1px solid #000000;
	}

#navEZPagesTOC ul {
	padding:  0.5em 0em;
	list-style-type: none;
	line-height: 1.5em;
	}

#navEZPagesTOC ul li {
	white-space: nowrap;
	}

#navEZPagesTOC ul li a {
	padding: 0em 0.5em;
	}

#navCategoryIcon, .buttonRow, #indexProductListCatDescription {
	}

#navMainSearch {
	float: right;
	}

#navBreadCrumb {
	background-color: #cc9900;
	}

#navEZPagesTop {
	background-color: #ffff33;
	}

#navBreadCrumb, #navEZPagesTop {
	font-size: 0.95em;
	font-weight: bold;
	margin: 0em;
	padding: 0.5em;
	}

#navColumnOne {
	}

#navColumnTwo {
	}