Slik asked the Answer Line forum how to save an entire website offline.
Saving just a page, even with images, is easy. (I'll get to saving a whole site in a moment.) In Firefox, for example, you select File - Save Page As. In the 'Save as type' field, select Web Page, complete, then save the file. Firefox will save the page as an HTML file, but will also save all the supporting files in a local folder.
Even this doesn't work perfectly, however. Complex formatting may not get properly reproduced.
I recommend HTTrack for saving an entire site. This free program will save all the pages within a domain, including images, while maintaining the link structure. It does not save the pages from external links like those in advertising.
The user interface is a bit ugly, and it throws up some techy terminology that not everyone will be comfortable with. But if you just stick with the default settings, everything should be fine.
Downloading a whole site can take some time, of course (I gave up on downloading pcworld.com while testing HTTrack). Luckily, once you've downloaded a site, HTTrack can also update it with new pages.
My thanks to Kylenstone of the forum for bringing HTTrack to my attention. Read the original forum discussion for Kylen's comments.