Chrisy,
Website design has less to do with the application you use and more to do with the planning you carry out. Once you know how to meet your customer's needs, have all your content sorted and sketched out the navigation system all you need is an HTML editor.
The absolute worse thing you can do is create a template and try to make your site fit. It will never work.
So to answer your question. the best wesite creator is a notebook and pencil followed by an HTML editor. I use dreamweaver. You can go buy the latest version but you can pick up a copy of DW4 for about £10 on ebay.
Or you can get one for free - just google for 'free HTML editor'.