I like the site, it looks really good so I'll give it a go. Short and to the point so please don't get offended.
From the top then:
- no point with zeroing out padding on body since there is no default padding
- 100% height on #wrapper may not be doing what you think it is
- Sami Designs is not a paragraph
- #nav li is invalid
- 500px height on #content-right doesn't really work since there is more than 500px of content there. It's always best not to specify a height and let the element expand to contain what you put in it. In this case, you float #updates but you don't put anything beside #updates...sort of the whole point of floats. At any rate, if an element contains floats you will need to understand how and when to clear them.
- .line should be a horizontal rule. See examples here.
- what is auto margins supposed to do on a full width element like #footer-content?
- #footer-title is so important you don't even style it. See divitis here.
- Extra contents is not a paragraph
- Website designed by ... is not a paragraph
- All those <div class="clear"></div> are just added markup. See the link above about clearing floats.
I think some padding on your .paragraph's p.line-right might help, the text is right up next to the border right now.
To show you why you need to clear your floats, look at your #footer-content with a background color like this -
Then clear the floats like this and see the difference -