best way to tackle cross browser compatibility

[daydreamer]

I am using CSS to layout my pages.

 

In firefox and chrome they display perfectly.

 

In each version of IE they display differently and the layout is messed up.

 

I am going to write a different css file for each version of internet explorer(5.5+).

 

is it best to use code like this:

<!--[if IE]>
  <link rel="stylesheet" type="text/css" href="ie.css" />
<![endif]-->

 

or write some PHP which uses $_SERVER['HTTP_USER_AGENT'] to find the browser type then echo the link to the right CSS file?

 

Thanks