Here is a simple, nice way of representing 404 error page. It is designed in the form of a blackboard with 404 written in a scratchy way and has clean fonts being used to write the rest of the content. The other features it provides are:

• Validate xhtml/css 1.0
• CUFON enabled
• PNG Fix for IE6
• PSD file included
• Compatibility (IE 6, IE 7 , IE 8, Firefox, Opera, Safari, Chrome)
• Help file included
• Links to others pages of the site
• Special Links for social networking sites

Web Elements                                                

Web Navigation based on 960 grids with XHTML /CSS        

Textures / Fills / Patterns