Quick question, dose Kile allow you to use the KDE System fonts in your LaTeX documents and if so what is the command to use them?

LaTeX cannot use system fonts. You need to use XeTeX instead.

The reason why you cannot use system fonts is that computer fonts are not used for typesetting where ligatures and kerning are used. You will find ligatures in some computer fonts and some programs will allow you to kern certain characters. But the LaTeX fonts are designed to allow ligatures, kerning and so on to be applied easily in fonts designed specifically for that purpose.

Don't tell everyone but you actually get some very expensive fonts free with LaTeX.

Well, using the free otf font Linux libertine with XeTeX you have more ligatures and other advances typographical features compared with normal LaTeX...
Also, otf fonts are defined with cubic splines, so the quality is really high.

Of course, that is the point of XeTeX, to extend the range of fonts. But, if the font was designed as a computing font rather than as a typesetting font, you will not get the same quality.

BTW in speaking of LaTeX I was including XeTeX and all the other contributions to the LaTeX ecosystem that enable it to produce high quality documents.

Thanks everyone, got it working.