An html website is static and doesn't change unless you go in and change the coding; coding can be done with various programs, or by hand.
A blog is a content management system(CMS): a CMS is a dynamic site, which is based on a database and is generated on the fly whenever someone visits the site. You have a database with slots for elements such as a header, a footer, sidebars, widgets and page content. When someone visits your site, the php code (a programming language usually used for blogs) queries the database and asks what should I put in this slot. Then it displays the page.
What this means is that updating the site is easy. If, for example, you have 100 pages on your site and you want to add the fact that you have a new book out, you must update 100 pages. But in a CMS, you only update one slot of a database, which updates everything. Or, if you want to change themes totally, you just change the template, which updates all the pages.
Blogs are usually organized on a reverse chronological basis, with the newest post on top. But most also have an option for pages that aren't in the timeline, and are displayed always. In Wordpress, which I use, there are Posts, which are the timeline posts in reverse chronological order, and there are Pages, which are the permanent pages outside the timeline posts.
If you want, you can use the Pages to create a site that looks like an html site. Just ignore the posts and you've got a "website."
There are a range of CMS programs from which to choose: Blogger, Wordpress, Joomla and others. Wordpress and Blogger are free sites that will have the URL extension of the site, such as FamousAuthor.Wordpress.com. Joomla can be only be hosted on your own domain, while Wordpress has a free option, or can be hosted on your own domain, which is what I do (http://www.darcypattison.com).
All of the major CMS have a support community where you can choose theme templates that determine how the site looks, and they are fairly easy to customize if you know just a bit of html or css. If you don't, then choose one that you like and just go with it. (Here's the Wordpress free themes page, where you can search by your criteria for design.) Or, you can go to something like Odesk.com and hire someone at a reasonable price to create a template for you.
One thing I look for these days in a template is will it adapt for mobile viewers. The one I am currently using on the site for my new book, WISDOM, THE MIDWAY ALBATROSS, http://wisdom.darcypattison.com, recognizes the device you are using to display the site and shows one, two, or three columns, whichever is appropriate. For iphones, it's one column; for ipads, it's two; for computers, it's three. In other words, don't be fooled by a "pretty" template. Go for functionality, too.
Or, look at the template for my site for my children's book, Prairie Storms, www.prairiestorms.com, which has a template specifically made for author. It features a book at the top and has other author-specific items. Here's a screen shot of that blog, showing the featured book and the author photo.
Whichever you choose, an html site or a blog, the key thing is content. What you write about is important; layout and design and the coding behind it all should just support what you have to say.
Darcy Pattison blogs about how-to-write at Fiction Notes.