There are 78 w3c validation errors in your HTML ... And I'm a firm believer of "lead by example", so I would suggest they get fixed soon ...
Click Here to see them ...
I agree that table borders are a bit too oldschool, but there are a few CSS border styles that look good ... As far as the colours go I would suggest checking out ...
http://www.colortools.net/color_matcher.html ... Which shows you how well two colours match.
Then the main nav-bar underneath your logo looks out of place to me, if you keep the backgrounds of the links white and rather make the text another colour it will make your logo look a lot cleaner aswell ...
You will learn how to create a quality website in easy steps
Id say you should rather "bold" those underlined words, otherwise it looks like a link.
Then I'd like to know what the grey area on the right hand side of each page is for, it's got no content in it, but yet it's there ... Maybe you could rather stretch the content so it fills that space aswell ...
On the "fonts" page where you name the different font (Arial, Times New Roman, Veranda), maybe you can put those words in that specific font so the user can see what the look like ...
Don't use to much different font types on a page
I would suggest someone else also re-reading your content for grammar or spelling errors like these ...
On the graphics page, under GIF's you can maybe mention that nowadays programs like Photoshop have the ability to save "optimised GIF's", which don't lack the quality that the old ones did, because it uses a customised palette, and show an example of that aswell ...
When I click on the "forms" page I get the dreaded HTTP404 error ... Also on the "line breaks" page and from "lists" downwards
<h1> H1 test</h1>
<h2> H1 test</h2>
<h3> H1 test</h3>
<h4> H1 test</h4>
<h5> H1 test</h5>
<h6> H1 test</h6>
Maybe you can replace "H1 Test with the relevant one ... for example H4 test"
You've also got two "background" pages ... Why not just one ... They both hold almost the same content, wouldn't it be better to merge them? Same with the "text and the "font" pages ...
Let's leave all our *plum* where it is and go live in the jungle ...