What makes a great landing page?

Right now, I'm redesiging my whole site which at the moment is just a blog with a link to the forum and my twitter account. What I want is to have a landing page which from there, users will be able to see the site. I want it to be responsive and also to be fun with vital information. I decided that maybe I will also offer services.
What I'm wanting to know is, should I create it in html5 and make it very niche and shiny or just keep it simple. Also what makes a great landing page?

See original post by shemseddine