If you are seriously interested in making websites. Your best bet for learning HTML is using http://www.w3schools.com/ as a reference and getting hold of a decent walkthrough. Have a clear idea of what you want in advance and then work it out as you go along. Also make a habit of viewing the source code of various designs you like regularly (Right click and view source). Over time you will begin to get an idea of how things are layed out but it's a long journey and you shouldn't expect to be making your dream site straight away.
If you simply want to get out a few sites quickly however you are likely better off hiring somebody. One thing that is definitely worth considering is using a content management system, more commonly known as a ‘CMS', such as WordPress or Joomla. These allow you to easily edit your site with a simple editor whilst a theme controls the look of your site.
In regards to HTML editors I have an ancient edition of dreamweaver the latest and greatest version of Creative Suite ;) that I sometimes use for visual editing but usually find myself falling back on NotePad++ for Windows and Text Wrangler for Mac which will highlight your code for you. This way you know that any code inserted is there for a reason rather than being added on a whim when Dreamweaver takes the long route to something.
I'm a huge advocate for WordPress personally as you design or purchase a theme once and it's applied to all of your pages and posts rather than having to build each individual pages look and appearance individually. There is also pretty much a plugin for anything that you can think of adding to your site and thousands of themes ready made to dive straight in.
Whilst only you can decide whether you want to actually learn to build websites or whether you simply need a website. There is a difference! For most entrepreneurs I would recommend that a base level of understanding would be a huge help but not a necessity. You can always hire someone to develop your website and then learn how to improve it along the way.